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Principal component regression

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394: 8912:(or the tuning parameter) inherently involved in its construction. While it does not completely discard any of the components, it exerts a shrinkage effect over all of them in a continuous manner so that the extent of shrinkage is higher for the low variance components and lower for the high variance components. Frank and Friedman (1993) conclude that for the purpose of prediction itself, the ridge estimator, owing to its smooth shrinkage effect, is perhaps a better choice compared to the PCR estimator having a discrete shrinkage effect. 4260: 8805:, which is probably more suited for addressing the multicollinearity problem and for performing dimension reduction, the above criteria actually attempts to improve the prediction and estimation efficiency of the PCR estimator by involving both the outcome as well as the covariates in the process of selecting the principal components to be used in the regression step. Alternative approaches with similar goals include selection of the principal components based on 9546:
exactly equivalent to the classical PCR based on a primal formulation. However, for arbitrary (and possibly non-linear) kernels, this primal formulation may become intractable owing to the infinite dimensionality of the associated feature map. Thus classical PCR becomes practically infeasible in that case, but kernel PCR based on the dual formulation still remains valid and computationally scalable.
3933: 6888: 6193: 4714: 4459: 8946:(PLS) estimator. Similar to PCR, PLS also uses derived covariates of lower dimensions. However unlike PCR, the derived covariates for PLS are obtained based on using both the outcome as well as the covariates. While PCR seeks the high variance directions in the space of the covariates, PLS seeks the directions in the covariate space that are most useful for the prediction of the outcome. 6560: 8465: 7854: 4255:{\displaystyle \operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{k})=\sigma ^{2}\;V_{k}(W_{k}^{T}W_{k})^{-1}V_{k}^{T}=\sigma ^{2}\;V_{k}\;\operatorname {diag} \left(\lambda _{1}^{-1},\ldots ,\lambda _{k}^{-1}\right)V_{k}^{T}=\sigma ^{2}\sideset {}{}\sum _{j=1}^{k}{\frac {\mathbf {v} _{j}\mathbf {v} _{j}^{T}}{\lambda _{j}}}.} 9446:
hence the corresponding principal components and principal component directions could be infinite-dimensional as well. Therefore, these quantities are often practically intractable under the kernel machine setting. Kernel PCR essentially works around this problem by considering an equivalent dual formulation based on using the
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that involves the observations for the explanatory variables only. Therefore, the resulting PCR estimator obtained from using these principal components as covariates need not necessarily have satisfactory predictive performance for the outcome. A somewhat similar estimator that tries to address this
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so obtained. It can be easily shown that this is the same as regressing the outcome vector on the corresponding principal components (which are finite-dimensional in this case), as defined in the context of the classical PCR. Thus, for the linear kernel, the kernel PCR based on a dual formulation is
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Clearly, kernel PCR has a discrete shrinkage effect on the eigenvectors of K', quite similar to the discrete shrinkage effect of classical PCR on the principal components, as discussed earlier. However, the feature map associated with the chosen kernel could potentially be infinite-dimensional, and
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covariates that turn out to be the most correlated with the outcome (based on the degree of significance of the corresponding estimated regression coefficients) are selected for further use. A conventional PCR, as described earlier, is then performed, but now it is based on only the
6422: 7715: 1630: 5941:. Since the smaller eigenvalues do not contribute significantly to the cumulative sum, the corresponding principal components may be continued to be dropped as long as the desired threshold limit is not exceeded. The same criteria may also be used for addressing the 7217: 8337: 7726: 6883:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{L}=\arg \min _{{\boldsymbol {\beta }}_{*}\in \mathbb {R} ^{p}}\|\mathbf {Y} -\mathbf {X} {\boldsymbol {\beta }}_{*}\|^{2}\quad {\text{ subject to }}\quad L_{(p-k)}^{T}{\boldsymbol {\beta }}_{*}=\mathbf {0} .} 6188:{\displaystyle \min _{{\boldsymbol {\beta }}_{*}\in \mathbb {R} ^{p}}\left\|\mathbf {Y} -\mathbf {X} {\boldsymbol {\beta }}_{*}\right\|^{2}\quad {\text{ subject to }}\quad {\boldsymbol {\beta }}_{*}\perp \{\mathbf {v} _{k+1},\ldots ,\mathbf {v} _{p}\}.} 5692: 4709:{\displaystyle \operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} })-\operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{k})=\sigma ^{2}\sideset {}{}\sum _{j=k+1}^{p}{\frac {\mathbf {v} _{j}\mathbf {v} _{j}^{T}}{\lambda _{j}}}.} 4454:{\displaystyle \operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{p})=\operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} })=\sigma ^{2}\sideset {}{}\sum _{j=1}^{p}{\frac {\mathbf {v} _{j}\mathbf {v} _{j}^{T}}{\lambda _{j}}}.} 3757: 1401: 3498: 3276: 2340: 836: 8717: 1231: 8953:
was proposed. In a spirit similar to that of PLS, it attempts at obtaining derived covariates of lower dimensions based on a criterion that involves both the outcome as well as the covariates. The method starts by performing a set of
8768:. In general, they may be estimated using the unrestricted least squares estimates obtained from the original full model. Park (1981) however provides a slightly modified set of estimates that may be better suited for this purpose. 1335: 8267: 7361: 5443: 9434:. The estimated regression coefficients (having the same dimension as the number of selected eigenvectors) along with the corresponding selected eigenvectors are then used for predicting the outcome for a future observation. In 525:. PCR can aptly deal with such situations by excluding some of the low-variance principal components in the regression step. In addition, by usually regressing on only a subset of all the principal components, PCR can result in 8473: 7865: 4769: 3089: 3155: 5591: 748: 9450:
of the associated kernel matrix. Under the linear regression model (which corresponds to choosing the kernel function as the linear kernel), this amounts to considering a spectral decomposition of the corresponding
6555:{\displaystyle \min _{{\boldsymbol {\beta }}_{*}\in \mathbb {R} ^{p}}\|\mathbf {Y} -\mathbf {X} {\boldsymbol {\beta }}_{*}\|^{2}\quad {\text{ subject to }}\quad L_{(p-k)}^{T}{\boldsymbol {\beta }}_{*}=\mathbf {0} } 6266: 5345: 8177: 8085: 7565: 7635: 2392: 7076: 1850: 1902: 1268: 7263: 1538: 8303: 8125: 8015: 7601: 7299: 6966: 6711: 6023: 3925: 3813: 578:
for the explanatory variables to obtain the principal components, and then (usually) select a subset, based on some appropriate criteria, of the principal components so obtained for further use.
8460:{\displaystyle \forall k\in \{1,\ldots ,p\}:\quad \operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} })-\operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{k})\succeq 0,} 7849:{\displaystyle \forall j\in \{1,\ldots ,p\}:\quad \operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} })-\operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{j})\succeq 0,} 1477: 7087: 6391: 9543: 9509: 8898: 8864: 8803: 5939: 5023: 2484: 2430: 2188: 1290: 1743: 2872: 8766: 8613: 8329: 8041: 7627: 7353: 5869:{\displaystyle \sum _{i=1}^{n}\left\|\mathbf {x} _{i}-V_{k}\mathbf {x} _{i}^{k}\right\|^{2}={\begin{cases}\sum _{j=k+1}^{n}\lambda _{j}&1\leqslant k<p\\0&k=p\end{cases}}} 4512: 3395: 1674: 1652: 1499: 5280: 5183: 9174: 9130: 9039: 7508: 4761: 3889: 3586: 3373: 2734: 2684: 1440: 6672: 5987: 5216: 2513: 3696: 1340: 3420: 3166: 2150: 2082: 2007: 6640: 2610: 2193: 8939: 5677: 5489: 4985: 4959: 3302: 2640: 2112: 1928: 1769: 1702: 1525: 1184: 1162: 1119: 1097: 1067: 1025: 997: 952: 8744: 4889: 753: 9475: 9377: 9086: 6930: 6602: 5136: 2966: 2787: 8648: 910: 8643: 2576: 2543: 1189: 5110: 3538: 3329: 2761: 640: 602: 568: 7452:{\displaystyle \operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} })=\operatorname {MSE} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} }),} 3687: 5073:. This issue can be effectively addressed through using a PCR estimator obtained by excluding the principal components corresponding to these small eigenvalues. 9059: 8995: 8972: 8584: 7979: 7319: 5901: 5655: 5631: 5611: 5509: 5239: 5071: 5043: 4909: 3833: 3658: 3634: 3614: 3415: 3006: 2986: 2940: 2827: 2807: 2450: 1295: 1045: 972: 930: 880: 860: 8185: 5356: 8559:{\displaystyle \operatorname {MSE} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} })-\operatorname {MSE} ({\widehat {\boldsymbol {\beta }}}_{k})\succeq 0} 7951:{\displaystyle \operatorname {MSE} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} })-\operatorname {MSE} ({\widehat {\boldsymbol {\beta }}}_{k})\succeq 0} 4855:{\displaystyle \operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} })-\operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{k})\succeq 0} 3015: 529:
through substantially lowering the effective number of parameters characterizing the underlying model. This can be particularly useful in settings with
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Thus, when only a proper subset of all the principal components are selected for regression, the PCR estimator so obtained is based on a hard form of
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evaluated at the corresponding pairs of covariate vectors. The pairwise inner products so obtained may therefore be represented in the form of a
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issue whereby the principal components corresponding to the smaller eigenvalues may be ignored as long as the threshold limit is maintained.
4939:, so that one can be linearly predicted from the others with a non-trivial degree of accuracy. Consequently, the columns of the data matrix 6204: 5285: 8138: 8046: 7710:{\displaystyle \operatorname {Var} ({\widehat {\boldsymbol {\beta }}}_{k})=\operatorname {MSE} ({\widehat {\boldsymbol {\beta }}}_{k}).} 5953:
Since the PCR estimator typically uses only a subset of all the principal components for regression, it can be viewed as some sort of a
7513: 654:(with dimension equal to the total number of covariates) for estimating the regression coefficients characterizing the original model. 2345: 6974: 1774: 1855: 424: 1625:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} }=(\mathbf {X} ^{T}\mathbf {X} )^{-1}\mathbf {X} ^{T}\mathbf {Y} } 334: 1236: 9310:
with the understanding that instead of the original set of covariates, the predictors are now given by the vector (potentially
7225: 9809: 9781: 839: 575: 8866:) as covariates in the model and discards the remaining low variance components (corresponding to the lower eigenvalues of 8615:, Park (1981) proposes the following guideline for selecting the principal components to be used for regression: Drop the 8272: 8094: 7984: 7570: 7268: 6935: 6680: 5992: 3894: 3762: 324: 7212:{\displaystyle \Lambda _{(p-k)}^{1/2}=\operatorname {diag} \left(\lambda _{k+1}^{1/2},\ldots ,\lambda _{p}^{1/2}\right).} 477: 5683: 3513:
The fitting process for obtaining the PCR estimator involves regressing the response vector on the derived data matrix
1453: 533:. Also, through appropriate selection of the principal components to be used for regression, PCR can lead to efficient 6277: 9645: 1074: 504: 9720:
Eric Bair; Trevor Hastie; Debashis Paul; Robert Tibshirani (2006). "Prediction by Supervised Principal Components".
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the outcome, the principal components with low variances may also be important, in some cases even more important.
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is such that the excluded principal components correspond to the smaller eigenvalues, thereby resulting in lower
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Sung H. Park (1981). "Collinearity and Optimal Restrictions on Regression Parameters for Estimating Responses".
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on the low variance components nullifying their contribution completely in the original model. In contrast, the
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Given the constrained minimization problem as defined above, consider the following generalized version of it:
5903:, the number of principal components to be used, through appropriate thresholding on the cumulative sum of the 2153: 9691:
Lldiko E. Frank & Jerome H. Friedman (1993). "A Statistical View of Some Chemometrics Regression Tools".
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under such situations. The variance expressions above indicate that these small eigenvalues have the maximum
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data matrix corresponding to the observations for the selected covariates. The number of covariates used:
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Practical implementation of this guideline of course requires estimates for the unknown model parameters
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that usually retains the high variance principal components (corresponding to the higher eigenvalues of
3752:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{p}={\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} }} 1396:{\displaystyle \;\operatorname {Var} \left({\boldsymbol {\varepsilon }}\right)=\sigma ^{2}I_{n\times n}} 480:. One typically uses only a subset of all the principal components for regression, making PCR a kind of 8817: 6645: 5960: 4936: 3493:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{k}=V_{k}{\widehat {\gamma }}_{k}\in \mathbb {R} ^{p}} 3271:{\displaystyle {\widehat {\gamma }}_{k}=(W_{k}^{T}W_{k})^{-1}W_{k}^{T}\mathbf {Y} \in \mathbb {R} ^{k}} 329: 298: 225: 5192: 4991:
losing its full column rank structure. More quantitatively, one or more of the smaller eigenvalues of
2489: 2335:{\displaystyle \Lambda _{p\times p}=\operatorname {diag} \left=\operatorname {diag} \left=\Delta ^{2}} 604:
Now regress the observed vector of outcomes on the selected principal components as covariates, using
5050: 5046: 319: 308: 272: 179: 9736: 5784: 2122: 2012: 1937: 9833: 9350: 9311: 9259: 9251: 9247: 9228: 9220: 6607: 6026: 4912: 2588: 1136: 974: 831:{\displaystyle \mathbf {X} _{n\times p}=\left(\mathbf {x} _{1},\ldots ,\mathbf {x} _{n}\right)^{T}} 613: 526: 380: 251: 174: 67: 46: 8922: 5660: 5451: 4968: 4942: 3285: 2618: 2095: 1911: 1752: 1685: 1508: 1167: 1145: 1102: 1080: 1050: 1008: 980: 935: 8722: 410: 303: 8712:{\displaystyle \lambda _{j}<(p\sigma ^{2})/{\boldsymbol {\beta }}^{T}{\boldsymbol {\beta }}.} 4868: 472:
In PCR, instead of regressing the dependent variable on the explanatory variables directly, the
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for predicting the outcome based on the covariates. However, it can be easily generalized to a
9065: 6896: 6568: 5115: 3690: 3279: 2945: 2766: 1502: 1226:{\displaystyle \mathbf {Y} =\mathbf {X} {\boldsymbol {\beta }}+{\boldsymbol {\varepsilon }},\;} 605: 267: 262: 204: 8977:(or univariate regressions) wherein the outcome vector is regressed separately on each of the 9773: 9767: 9570: 8943: 8593:
In order to ensure efficient estimation and prediction performance of PCR as an estimator of
5241: 5219: 4988: 3009: 1528: 889: 643: 355: 51: 8618: 8087:, based on using the mean squared error as the performance criteria. In addition, any given 2551: 2518: 9580: 8587: 8306: 7604: 7330: 5634: 5088: 3516: 3307: 2739: 1532: 375: 365: 246: 214: 169: 148: 56: 1330:{\displaystyle \operatorname {E} \left({\boldsymbol {\varepsilon }}\right)=\mathbf {0} \;} 626: 588: 554: 8: 9319: 9299: 9287: 9201: 8901: 8829: 8262:{\displaystyle k\in \{1,\ldots ,p\},V_{(p-k)}^{T}{\boldsymbol {\beta }}\neq \mathbf {0} } 8018: 5880: 5082: 4962: 3666: 883: 485: 450: 293: 194: 189: 143: 92: 82: 27: 5438:{\displaystyle \sum _{i=1}^{n}\left\|\mathbf {x} _{i}-L_{k}\mathbf {z} _{i}\right\|^{2}} 9619: 9414:
of K' is obtained. Kernel PCR then proceeds by (usually) selecting a subset of all the
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problem which arises when two or more of the explanatory variables are close to being
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of the explanatory variables) are selected as regressors. However, for the purpose of
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criteria. Often, the principal components are also selected based on their degree of
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Jolliffe, Ian T. (1982). "A note on the Use of Principal Components in Regression".
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of the selected principal component directions, and consequently restricts it to be
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and then regressing the outcome vector on a selected subset of the eigenvectors of
9435: 8905: 1126: 1070: 209: 138: 3084:{\displaystyle \mathbf {x} _{i}^{k}=V_{k}^{T}\mathbf {x} _{i}\in \mathbb {R} ^{k}} 9763: 8810: 3150:{\displaystyle \mathbf {x} _{i}\in \mathbb {R} ^{p}\;\;\forall \;\;1\leq i\leq n} 650:(the eigenvectors corresponding to the selected principal components) to get the 370: 77: 5586:{\displaystyle \mathbf {z} _{i}=\mathbf {x} _{i}^{k}=V_{k}^{T}\mathbf {x} _{i},} 9745: 9387: 9338: 9323: 9315: 9303: 9295: 9275: 9267: 9239: 9197: 6405: 3589: 3541: 2085: 1654:. PCR is another technique that may be used for the same purpose of estimating 122: 9822: 9693: 9664: 9399: 9346: 9342: 9334: 9255: 1931: 743:{\displaystyle \mathbf {Y} _{n\times 1}=\left(y_{1},\ldots ,y_{n}\right)^{T}} 241: 117: 6411: 9427: 9423: 9415: 9330: 6401: 646:
this vector back to the scale of the actual covariates, using the selected
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selected principal components as covariates is equivalent to carrying out
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that correspond to the observations for these covariates tend to become
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of the PCR estimator has a lower variance compared to that of the same
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Unlike the criteria based on the cumulative sum of the eigenvalues of
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When all the principal components are selected for regression so that
9283: 9279: 9213: 9205: 6261:{\displaystyle V_{(p-k)}^{T}{\boldsymbol {\beta }}_{*}=\mathbf {0} ,} 1448: 522: 9677: 9615: 9345:
among the feature maps for the observed covariate vectors and these
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denotes the unknown parameter vector of regression coefficients and
5340:{\displaystyle \mathbf {z} _{i}\in \mathbb {R} ^{k}(1\leq i\leq n)} 3278:
denote the vector of estimated regression coefficients obtained by
1404: 492: 9341:. It turns out that it is only sufficient to compute the pairwise 8172:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} }} 8080:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{\mathrm {ols} }} 9690: 3504:
Fundamental characteristics and applications of the PCR estimator
7560:{\displaystyle V_{(p-k)}^{T}{\boldsymbol {\beta }}=\mathbf {0} } 2452:
denote the corresponding orthonormal set of eigenvectors. Then,
2387:{\displaystyle \lambda _{1}\geq \cdots \geq \lambda _{p}\geq 0} 7071:{\displaystyle L_{(p-k)}^{*}=V_{(p-k)}\Lambda _{(p-k)}^{1/2},} 1845:{\displaystyle \Delta _{p\times p}=\operatorname {diag} \left} 1501:, based on the data. One frequently used approach for this is 1077:. This centering step is crucial (at least for the columns of 545:
The PCR method may be broadly divided into three major steps:
1897:{\displaystyle \delta _{1}\geq \cdots \geq \delta _{p}\geq 0} 612:) to get a vector of estimated regression coefficients (with 8915:
In addition, the principal components are obtained from the
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PCR starts by performing a PCA on the centered data matrix
1263:{\displaystyle {\boldsymbol {\beta }}\in \mathbb {R} ^{p}} 9379:
symmetric non-negative definite matrix also known as the
7258:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{L^{*}}} 6412:
Optimality of PCR among a class of regularized estimators
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to each other. Thus in the regression step, performing a
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denoting the non-negative eigenvalues (also known as the
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turns out to be a special case of this setting when the
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The classical PCR method as described above is based on
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and the subsequent number of principal components used:
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on the variance of the least squares estimator, thereby
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matrix with orthonormal columns consisting of the first
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estimator exerts a smooth shrinkage effect through the
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may be viewed as the data matrix obtained by using the
3640:(or univariate regressions) separately on each of the 616:
equal to the number of selected principal components).
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to be used for regression are usually selected using
9359: 9138: 9094: 9068: 9047: 9003: 8983: 8960: 8925: 8872: 8838: 8777: 8752: 8725: 8651: 8621: 8599: 8572: 8476: 8340: 8315: 8298:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{k}} 8275: 8188: 8141: 8120:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{k}} 8097: 8049: 8027: 8010:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{k}} 7987: 7967: 7868: 7729: 7638: 7613: 7596:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{k}} 7573: 7516: 7472: 7364: 7339: 7307: 7294:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{k}} 7271: 7228: 7090: 6977: 6961:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{L}} 6938: 6899: 6722: 6706:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{L}} 6683: 6648: 6610: 6571: 6425: 6280: 6207: 6038: 6018:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{k}} 5995: 5963: 5913: 5889: 5695: 5663: 5643: 5619: 5599: 5517: 5497: 5454: 5359: 5288: 5249: 5227: 5195: 5144: 5118: 5091: 5059: 5031: 4997: 4971: 4945: 4897: 4871: 4772: 4725: 4523: 4470: 4274: 3936: 3920:{\displaystyle {\widehat {\boldsymbol {\beta }}}_{k}} 3897: 3853: 3821: 3808:{\displaystyle W_{p}=\mathbf {X} V_{p}=\mathbf {X} V} 3765: 3699: 3669: 3646: 3622: 3602: 3550: 3519: 3423: 3403: 3381: 3337: 3310: 3288: 3169: 3097: 3018: 2994: 2974: 2948: 2879: 2835: 2815: 2795: 2769: 2742: 2698: 2648: 2621: 2591: 2554: 2521: 2492: 2458: 2438: 2404: 2348: 2196: 2162: 2125: 2098: 2015: 1940: 1914: 1858: 1777: 1755: 1710: 1688: 1660: 1638: 1541: 1511: 1485: 1456: 1413: 1343: 1298: 1276: 1239: 1192: 1170: 1148: 1105: 1083: 1053: 1033: 1011: 983: 960: 938: 918: 892: 868: 848: 756: 672: 629: 591: 557: 9208:
in the covariates, but instead it can belong to the
9183: 6968:achieves the minimum prediction error is given by: 5053:the estimator significantly when they are close to 9603:Journal of the Royal Statistical Society, Series C 9537: 9503: 9469: 9371: 9168: 9124: 9080: 9053: 9033: 8989: 8966: 8933: 8892: 8858: 8797: 8760: 8738: 8711: 8637: 8607: 8578: 8558: 8459: 8323: 8297: 8261: 8171: 8119: 8079: 8035: 8009: 7973: 7950: 7848: 7709: 7621: 7595: 7559: 7502: 7451: 7347: 7313: 7293: 7257: 7211: 7070: 6960: 6924: 6893:Then the optimal choice of the restriction matrix 6882: 6705: 6666: 6634: 6596: 6554: 6385: 6260: 6187: 6025:denotes the regularized solution to the following 6017: 5981: 5933: 5895: 5868: 5671: 5649: 5633:dimensional principal components provide the best 5625: 5605: 5585: 5503: 5483: 5437: 5339: 5274: 5233: 5210: 5177: 5130: 5104: 5065: 5037: 5017: 4979: 4953: 4903: 4883: 4854: 4755: 4708: 4506: 4453: 4254: 3919: 3883: 3827: 3807: 3751: 3681: 3652: 3628: 3608: 3580: 3532: 3492: 3409: 3389: 3367: 3323: 3296: 3270: 3149: 3083: 3000: 2980: 2960: 2934: 2866: 2821: 2801: 2781: 2755: 2728: 2678: 2634: 2604: 2570: 2537: 2507: 2478: 2444: 2424: 2386: 2334: 2182: 2144: 2106: 2076: 2001: 1922: 1896: 1844: 1763: 1737: 1696: 1668: 1646: 1624: 1519: 1493: 1471: 1434: 1395: 1329: 1284: 1262: 1225: 1178: 1156: 1113: 1091: 1061: 1039: 1019: 991: 966: 946: 924: 904: 874: 854: 830: 742: 634: 596: 562: 9713: 8949:2006 a variant of the classical PCR known as the 4625: 4376: 4177: 1472:{\displaystyle {\widehat {\boldsymbol {\beta }}}} 9820: 6752: 6427: 6386:{\displaystyle V_{(p-k)}=\left_{p\times (p-k)}.} 6198:The constraint may be equivalently written as: 6040: 5025:get(s) very close or become(s) exactly equal to 886:and the number of covariates respectively, with 9723:Journal of the American Statistical Association 8997:covariates taken one at a time. Then, for some 7222:Quite clearly, the resulting optimal estimator 5511:principal component directions as columns, and 4926: 7329:Since the ordinary least squares estimator is 6400:that constrains the resulting solution to the 3689:, then the PCR estimator is equivalent to the 3660:selected principal components as a covariate. 9657: 9655: 9653: 6604:denotes any full column rank matrix of order 418: 9661: 9538:{\displaystyle \mathbf {X} \mathbf {X} ^{T}} 9504:{\displaystyle \mathbf {X} \mathbf {X} ^{T}} 9163: 9145: 9119: 9101: 9028: 9010: 8893:{\displaystyle \mathbf {X} ^{T}\mathbf {X} } 8859:{\displaystyle \mathbf {X} ^{T}\mathbf {X} } 8798:{\displaystyle \mathbf {X} ^{T}\mathbf {X} } 8368: 8350: 8213: 8195: 7757: 7739: 7497: 7479: 6814: 6785: 6489: 6460: 6179: 6137: 5934:{\displaystyle \mathbf {X} ^{T}\mathbf {X} } 5169: 5151: 5018:{\displaystyle \mathbf {X} ^{T}\mathbf {X} } 4750: 4732: 4501: 4477: 3878: 3860: 3575: 3557: 3362: 3344: 2723: 2705: 2673: 2655: 2479:{\displaystyle \mathbf {X} \mathbf {v} _{j}} 2425:{\displaystyle \mathbf {X} ^{T}\mathbf {X} } 2183:{\displaystyle \mathbf {X} ^{T}\mathbf {X} } 1285:{\displaystyle {\boldsymbol {\varepsilon }}} 999:denotes the corresponding observed outcome. 517:One major use of PCR lies in overcoming the 9242:setting, the vector of covariates is first 8942:issue through its very construction is the 5138:matrix having orthonormal columns, for any 4935:, two or more of the covariates are highly 1447:The primary goal is to obtain an efficient 750:denote the vector of observed outcomes and 537:of the outcome based on the assumed model. 491:Often the principal components with higher 9650: 9638:The Oxford Dictionary of Statistical Terms 8823: 7265:is then simply given by the PCR estimator 4072: 4061: 3981: 3131: 3130: 3126: 3125: 1738:{\displaystyle \mathbf {X} =U\Delta V^{T}} 1431: 1430: 1344: 1326: 1222: 631: 630: 593: 592: 559: 558: 457:(PCA). More specifically, PCR is used for 425: 411: 9735: 6773: 6713:denote the corresponding solution. Thus 6448: 6061: 5613:dimensional derived covariates. Thus the 5306: 4923:of the ordinary least squares estimator. 4891:indicates that a square symmetric matrix 3759:. This is easily seen from the fact that 3480: 3258: 3115: 3091:instead of using the original covariates 3071: 1292:denotes the vector of random errors with 1250: 476:of the explanatory variables are used as 9599: 9422:of the outcome vector on these selected 9390:setting can now be implemented by first 9212:associated with any arbitrary (possibly 5948: 954:denotes one set of observations for the 658: 9762: 8754: 8702: 8691: 8601: 8532: 8490: 8430: 8388: 8317: 8280: 8247: 8146: 8102: 8054: 8029: 7992: 7981:. Thus in that case, the corresponding 7924: 7882: 7819: 7777: 7686: 7652: 7615: 7578: 7545: 7420: 7378: 7341: 7276: 7233: 6943: 6859: 6803: 6758: 6727: 6688: 6534: 6478: 6433: 6237: 6124: 6094: 6046: 6000: 4828: 4786: 4579: 4537: 4322: 4288: 3950: 3902: 3726: 3704: 3508: 3428: 3383: 2867:{\displaystyle W_{k}=\mathbf {X} V_{k}} 1662: 1640: 1546: 1487: 1460: 1356: 1310: 1278: 1241: 1215: 1207: 1099:) since PCR involves the use of PCA on 9821: 9349:are simply given by the values of the 9337:without ever explicitly computing the 9333:actually enables us to operate in the 8761:{\displaystyle {\boldsymbol {\beta }}} 8608:{\displaystyle {\boldsymbol {\beta }}} 8324:{\displaystyle {\boldsymbol {\beta }}} 8036:{\displaystyle {\boldsymbol {\beta }}} 7622:{\displaystyle {\boldsymbol {\beta }}} 7348:{\displaystyle {\boldsymbol {\beta }}} 6932:for which the corresponding estimator 5957:procedure. More specifically, for any 5076: 4507:{\displaystyle k\in \{1,\ldots ,p-1\}} 3390:{\displaystyle {\boldsymbol {\beta }}} 1669:{\displaystyle {\boldsymbol {\beta }}} 1647:{\displaystyle {\boldsymbol {\beta }}} 1494:{\displaystyle {\boldsymbol {\beta }}} 977:covariate and the respective entry of 9790: 9772:. Harvard University Press. pp.  9278:, corresponds to one feature (may be 5275:{\displaystyle L_{k}\mathbf {z} _{i}} 5178:{\displaystyle k\in \{1,\ldots ,p\}.} 3842: 2988:principal components as its columns. 9169:{\displaystyle k\in \{1,\ldots ,m\}} 9125:{\displaystyle m\in \{1,\ldots ,p\}} 9034:{\displaystyle m\in \{1,\ldots ,p\}} 7503:{\displaystyle k\in \{1,\ldots ,p\}} 5081:PCR may also be used for performing 4756:{\displaystyle k\in \{1,\ldots ,p\}} 3884:{\displaystyle k\in \{1,\ldots ,p\}} 3581:{\displaystyle k\in \{1,\ldots ,p\}} 3368:{\displaystyle k\in \{1,\ldots ,p\}} 2729:{\displaystyle k\in \{1,\ldots ,p\}} 2679:{\displaystyle j\in \{1,\ldots ,p\}} 1435:{\displaystyle \sigma ^{2}>0\;\;} 8645:principal component if and only if 5189:each of the covariate observations 4627: 4378: 4179: 3588:since the principal components are 13: 9756: 9438:, this technique is also known as 9418:so obtained and then performing a 8507: 8504: 8501: 8405: 8402: 8399: 8341: 8163: 8160: 8157: 8071: 8068: 8065: 7899: 7896: 7893: 7794: 7791: 7788: 7730: 7437: 7434: 7431: 7395: 7392: 7389: 7092: 7031: 4803: 4800: 4797: 4554: 4551: 4548: 4339: 4336: 4333: 3743: 3740: 3737: 3417:principal components is given by: 3282:regression of the response vector 3127: 2323: 2198: 2129: 1779: 1722: 1563: 1560: 1557: 1299: 1135:Following centering, the standard 14: 9845: 9184:Generalization to kernel settings 8828:In general, PCR is essentially a 6667:{\displaystyle 1\leqslant k<p} 5982:{\displaystyle 1\leqslant k<p} 9561:Partial least squares regression 9525: 9519: 9491: 9485: 9322:the actual covariates using the 9210:Reproducing Kernel Hilbert Space 8927: 8886: 8875: 8852: 8841: 8791: 8780: 8255: 7553: 6873: 6797: 6789: 6548: 6472: 6464: 6341: 6314: 6251: 6169: 6142: 6088: 6080: 5927: 5916: 5750: 5725: 5665: 5570: 5535: 5520: 5414: 5389: 5291: 5262: 5211:{\displaystyle \mathbf {x} _{i}} 5198: 5011: 5000: 4973: 4947: 4675: 4663: 4420: 4408: 4221: 4209: 3798: 3780: 3290: 3249: 3100: 3056: 3021: 2919: 2913: 2893: 2887: 2850: 2508:{\displaystyle \mathbf {v} _{j}} 2495: 2466: 2460: 2418: 2407: 2176: 2165: 2100: 2061: 2040: 1986: 1965: 1916: 1757: 1712: 1690: 1618: 1607: 1588: 1577: 1513: 1322: 1202: 1194: 1172: 1150: 1107: 1085: 1055: 1013: 985: 940: 882:denote the size of the observed 807: 786: 759: 675: 540: 467:standard linear regression model 392: 8374: 7763: 6829: 6823: 6504: 6498: 6121: 6115: 2090:left and right singular vectors 340:Least-squares spectral analysis 278:Generalized estimating equation 98:Multinomial logistic regression 73:Vector generalized linear model 9707:10.1080/00401706.1993.10485033 9630: 9593: 8681: 8665: 8547: 8525: 8513: 8483: 8445: 8423: 8411: 8381: 8236: 8224: 7939: 7917: 7905: 7875: 7834: 7812: 7800: 7770: 7701: 7679: 7667: 7645: 7534: 7522: 7443: 7413: 7401: 7371: 7108: 7096: 7047: 7035: 7025: 7013: 6995: 6983: 6917: 6905: 6847: 6835: 6629: 6617: 6589: 6577: 6522: 6510: 6375: 6363: 6298: 6286: 6225: 6213: 6105: 6075: 5766: 5719: 5425: 5383: 5334: 5316: 4843: 4821: 4809: 4779: 4594: 4572: 4560: 4530: 4345: 4315: 4303: 4281: 4021: 3992: 3965: 3943: 3221: 3192: 2929: 2883: 2145:{\displaystyle V\Lambda V^{T}} 2077:{\displaystyle V_{p\times p}=} 2071: 2035: 2002:{\displaystyle U_{n\times p}=} 1996: 1960: 1593: 1572: 1073:so that all of them have zero 842:of observed covariates where, 443:principal component regression 1: 9586: 9398:(K, say) with respect to the 8900:). Thus it exerts a discrete 8182:Now suppose that for a given 8131:compared to that of the same 7324: 6635:{\displaystyle p\times (p-k)} 3375:, the final PCR estimator of 2605:{\displaystyle j^{\text{th}}} 2579:principal component direction 484:procedure and also a type of 159:Nonlinear mixed-effects model 9556:Principal component analysis 9266:so obtained is known as the 8934:{\displaystyle \mathbf {X} } 6408:to the excluded directions. 5883:may be achieved by choosing 5672:{\displaystyle \mathbf {X} } 5657:to the observed data matrix 5484:{\displaystyle L_{k}=V_{k},} 5350:Then, it can be shown that 5185:Suppose now that we want to 4980:{\displaystyle \mathbf {X} } 4954:{\displaystyle \mathbf {X} } 4927:Addressing multicollinearity 4614: 4365: 4166: 3297:{\displaystyle \mathbf {Y} } 2635:{\displaystyle \lambda _{j}} 2107:{\displaystyle \mathbf {X} } 1923:{\displaystyle \mathbf {X} } 1764:{\displaystyle \mathbf {X} } 1747:singular value decomposition 1697:{\displaystyle \mathbf {X} } 1520:{\displaystyle \mathbf {X} } 1179:{\displaystyle \mathbf {X} } 1157:{\displaystyle \mathbf {Y} } 1114:{\displaystyle \mathbf {X} } 1092:{\displaystyle \mathbf {X} } 1062:{\displaystyle \mathbf {X} } 1020:{\displaystyle \mathbf {Y} } 992:{\displaystyle \mathbf {Y} } 947:{\displaystyle \mathbf {X} } 499:corresponding to the higher 455:principal component analysis 7: 9549: 9300:underlying regression model 8739:{\displaystyle \sigma ^{2}} 7720:We have already seen that 1505:regression which, assuming 531:high-dimensional covariates 453:technique that is based on 361:Mean and predicted response 10: 9850: 9797:Principles of Econometrics 9746:10.1198/016214505000000628 9420:standard linear regression 8470:it is still possible that 5491:the matrix with the first 4915:. Consequently, any given 4884:{\displaystyle A\succeq 0} 3594:multiple linear regression 1904:denoting the non-negative 508:variance-covariance matrix 154:Linear mixed-effects model 9470:{\displaystyle n\times n} 9372:{\displaystyle n\times n} 9306:setting is essentially a 9286:) of the covariates. The 9081:{\displaystyle n\times m} 8975:simple linear regressions 8269:. Then the corresponding 7567:, then the corresponding 6925:{\displaystyle L_{(p-k)}} 6597:{\displaystyle L_{(p-k)}} 5131:{\displaystyle p\times k} 3638:simple linear regressions 3397:based on using the first 2961:{\displaystyle n\times k} 2782:{\displaystyle p\times k} 2118:The principal components: 838:denote the corresponding 320:Least absolute deviations 9290:is then assumed to be a 9221:positive-definite kernel 9204:need not necessarily be 9176:are usually selected by 8910:regularization parameter 8127:would also have a lower 7510:, we additionally have: 6027:constrained minimization 3815:and also observing that 2968:matrix having the first 2515:respectively denote the 2088:of vectors denoting the 68:Generalized linear model 9392:appropriately centering 9308:linear regression model 9225:linear regression model 9194:linear regression model 8824:Shrinkage effect of PCR 7462:where, MSE denotes the 2585:) corresponding to the 2432:, while the columns of 1186:can be represented as: 905:{\displaystyle n\geq p} 463:regression coefficients 9539: 9505: 9471: 9448:spectral decomposition 9408:centered kernel matrix 9402:and then performing a 9373: 9238:In general, under the 9170: 9126: 9082: 9055: 9035: 8991: 8968: 8935: 8894: 8860: 8799: 8762: 8740: 8713: 8639: 8638:{\displaystyle j^{th}} 8609: 8580: 8560: 8461: 8325: 8299: 8263: 8173: 8121: 8081: 8037: 8011: 7975: 7952: 7850: 7711: 7623: 7597: 7561: 7504: 7453: 7349: 7321:principal components. 7315: 7295: 7259: 7213: 7072: 6962: 6926: 6884: 6826: subject to  6707: 6668: 6636: 6598: 6556: 6501: subject to  6387: 6262: 6189: 6118: subject to  6019: 5983: 5935: 5897: 5870: 5813: 5716: 5673: 5651: 5627: 5607: 5587: 5505: 5485: 5439: 5380: 5341: 5276: 5235: 5212: 5179: 5132: 5106: 5067: 5039: 5019: 4981: 4955: 4905: 4885: 4856: 4757: 4710: 4654: 4508: 4455: 4399: 4256: 4200: 3921: 3885: 3829: 3809: 3753: 3691:ordinary least squares 3683: 3654: 3630: 3610: 3582: 3534: 3494: 3411: 3391: 3369: 3325: 3298: 3280:ordinary least squares 3272: 3151: 3085: 3002: 2982: 2962: 2936: 2868: 2823: 2803: 2783: 2757: 2730: 2680: 2636: 2606: 2572: 2571:{\displaystyle j^{th}} 2539: 2538:{\displaystyle j^{th}} 2509: 2480: 2446: 2426: 2388: 2336: 2184: 2154:spectral decomposition 2146: 2108: 2078: 2003: 1924: 1898: 1846: 1765: 1739: 1698: 1670: 1648: 1626: 1521: 1503:ordinary least squares 1495: 1473: 1436: 1397: 1331: 1286: 1264: 1227: 1180: 1158: 1115: 1093: 1063: 1041: 1021: 993: 968: 948: 926: 906: 876: 856: 832: 744: 636: 606:ordinary least squares 598: 564: 399:Mathematics portal 325:Iteratively reweighted 9769:Advanced Econometrics 9571:Canonical correlation 9540: 9506: 9472: 9410:(K', say) whereby an 9374: 9258:characterized by the 9171: 9127: 9083: 9056: 9036: 8992: 8969: 8944:partial least squares 8936: 8895: 8861: 8800: 8763: 8741: 8714: 8640: 8610: 8581: 8561: 8462: 8326: 8300: 8264: 8174: 8122: 8091:of the corresponding 8082: 8038: 8012: 7976: 7953: 7851: 7712: 7624: 7598: 7562: 7505: 7454: 7350: 7316: 7296: 7260: 7214: 7073: 6963: 6927: 6885: 6708: 6669: 6637: 6599: 6557: 6388: 6263: 6190: 6020: 5984: 5949:Regularization effect 5936: 5898: 5871: 5787: 5696: 5674: 5652: 5628: 5608: 5588: 5506: 5486: 5440: 5360: 5342: 5277: 5242:linear transformation 5236: 5213: 5180: 5133: 5107: 5105:{\displaystyle L_{k}} 5068: 5040: 5020: 4982: 4956: 4913:non-negative definite 4906: 4886: 4857: 4758: 4711: 4610: 4509: 4456: 4361: 4257: 4162: 3922: 3886: 3830: 3810: 3754: 3684: 3655: 3631: 3611: 3583: 3535: 3533:{\displaystyle W_{k}} 3495: 3412: 3392: 3370: 3326: 3324:{\displaystyle W_{k}} 3299: 3273: 3152: 3086: 3003: 2983: 2963: 2937: 2869: 2824: 2804: 2784: 2758: 2756:{\displaystyle V_{k}} 2731: 2681: 2637: 2607: 2573: 2540: 2510: 2481: 2447: 2427: 2389: 2337: 2185: 2147: 2109: 2079: 2004: 1925: 1899: 1847: 1766: 1740: 1699: 1671: 1649: 1627: 1522: 1496: 1474: 1437: 1398: 1332: 1287: 1265: 1228: 1181: 1159: 1116: 1094: 1064: 1042: 1022: 994: 969: 949: 927: 907: 877: 857: 833: 745: 659:Details of the method 637: 599: 565: 356:Regression validation 335:Bayesian multivariate 52:Polynomial regression 16:Statistical technique 9581:Total sum of squares 9515: 9481: 9455: 9357: 9312:infinite-dimensional 9274:, also known as the 9252:infinite-dimensional 9231:is chosen to be the 9200:setting whereby the 9136: 9092: 9066: 9045: 9001: 8981: 8958: 8923: 8870: 8836: 8775: 8750: 8723: 8649: 8619: 8597: 8570: 8474: 8338: 8313: 8273: 8186: 8139: 8095: 8047: 8025: 7985: 7965: 7961:for that particular 7866: 7859:which then implies: 7727: 7636: 7611: 7571: 7514: 7470: 7362: 7337: 7305: 7269: 7226: 7088: 6975: 6936: 6897: 6720: 6681: 6646: 6608: 6569: 6423: 6278: 6205: 6036: 5993: 5989:, the PCR estimator 5961: 5911: 5887: 5693: 5684:reconstruction error 5661: 5641: 5635:linear approximation 5617: 5597: 5515: 5495: 5452: 5357: 5286: 5247: 5225: 5193: 5142: 5116: 5089: 5057: 5029: 4995: 4969: 4943: 4895: 4869: 4770: 4723: 4620: 4521: 4468: 4371: 4272: 4172: 3934: 3895: 3851: 3819: 3763: 3697: 3667: 3644: 3620: 3600: 3548: 3517: 3509:Two basic properties 3421: 3401: 3379: 3335: 3308: 3286: 3167: 3095: 3016: 2992: 2972: 2946: 2877: 2833: 2813: 2793: 2767: 2740: 2696: 2646: 2619: 2589: 2552: 2519: 2490: 2456: 2436: 2402: 2346: 2194: 2160: 2123: 2096: 2013: 1938: 1912: 1856: 1775: 1753: 1708: 1686: 1658: 1636: 1539: 1509: 1483: 1454: 1411: 1341: 1296: 1274: 1237: 1190: 1168: 1146: 1103: 1081: 1051: 1031: 1009: 1003:Data pre-processing: 981: 958: 936: 916: 890: 866: 846: 754: 670: 664:Data representation: 635:{\displaystyle \;\;} 627: 597:{\displaystyle \;\;} 589: 563:{\displaystyle \;\;} 555: 474:principal components 381:Gauss–Markov theorem 376:Studentized residual 366:Errors and residuals 200:Principal components 170:Nonlinear regression 57:General linear model 9829:Regression analysis 9440:spectral regression 9288:regression function 9202:regression function 8917:eigen-decomposition 8830:shrinkage estimator 8245: 8019:efficient estimator 7543: 7466:. Now, if for some 7301:based on the first 7200: 7168: 7125: 7064: 7004: 6856: 6531: 6234: 5881:dimension reduction 5879:Thus any potential 5764: 5567: 5549: 5085:. To see this, let 5083:dimension reduction 5077:Dimension reduction 4689: 4622: 4616: 4434: 4373: 4367: 4235: 4174: 4168: 4148: 4128: 4101: 4047: 4009: 3682:{\displaystyle k=p} 3590:mutually orthogonal 3304:on the data matrix 3247: 3209: 3053: 3035: 2690:Derived covariates: 2546:principal component 2313: 2289: 652:final PCR estimator 527:dimension reduction 495:(the ones based on 486:shrinkage estimator 451:regression analysis 226:Errors-in-variables 93:Logistic regression 83:Binomial regression 28:Regression analysis 22:Part of a series on 9800:. Wiley. pp.  9535: 9501: 9467: 9412:eigendecomposition 9369: 9292:linear combination 9166: 9122: 9078: 9051: 9031: 8987: 8964: 8931: 8890: 8856: 8820:with the outcome. 8795: 8758: 8736: 8709: 8635: 8605: 8576: 8556: 8457: 8331:. However, since 8321: 8295: 8259: 8219: 8169: 8129:mean squared error 8117: 8077: 8033: 8007: 7971: 7948: 7846: 7707: 7619: 7593: 7557: 7517: 7500: 7464:mean squared error 7449: 7345: 7311: 7291: 7255: 7209: 7178: 7140: 7091: 7068: 7030: 6978: 6958: 6922: 6880: 6830: 6784: 6703: 6664: 6632: 6594: 6552: 6505: 6459: 6383: 6258: 6208: 6185: 6072: 6015: 5979: 5931: 5893: 5866: 5861: 5748: 5682:The corresponding 5669: 5647: 5623: 5603: 5593:the corresponding 5583: 5553: 5533: 5501: 5481: 5435: 5337: 5272: 5231: 5208: 5175: 5128: 5102: 5063: 5035: 5015: 4977: 4963:linearly dependent 4951: 4901: 4881: 4852: 4753: 4706: 4673: 4504: 4451: 4418: 4252: 4219: 4134: 4111: 4084: 4033: 3995: 3917: 3891:, the variance of 3881: 3843:Variance reduction 3825: 3805: 3749: 3679: 3650: 3626: 3606: 3578: 3530: 3490: 3407: 3387: 3365: 3321: 3294: 3268: 3233: 3195: 3161:The PCR estimator: 3147: 3081: 3039: 3019: 2998: 2978: 2958: 2932: 2864: 2819: 2799: 2779: 2753: 2726: 2676: 2632: 2602: 2568: 2535: 2505: 2476: 2442: 2422: 2384: 2332: 2299: 2275: 2180: 2142: 2104: 2074: 1999: 1920: 1894: 1842: 1761: 1735: 1694: 1666: 1644: 1622: 1533:unbiased estimator 1517: 1491: 1479:for the parameter 1469: 1432: 1393: 1327: 1282: 1260: 1223: 1176: 1154: 1111: 1089: 1069:have already been 1059: 1037: 1017: 989: 964: 944: 922: 902: 872: 852: 828: 740: 632: 594: 560: 113:Multinomial probit 9811:978-0-471-85845-4 9783:978-0-674-00560-0 9636:Dodge, Y. (2003) 9576:Deming regression 9054:{\displaystyle m} 8990:{\displaystyle p} 8967:{\displaystyle p} 8579:{\displaystyle k} 8538: 8496: 8436: 8394: 8286: 8152: 8108: 8060: 7998: 7974:{\displaystyle k} 7930: 7888: 7825: 7783: 7692: 7658: 7584: 7426: 7384: 7314:{\displaystyle k} 7282: 7239: 6949: 6827: 6751: 6733: 6694: 6502: 6426: 6119: 6039: 6006: 5943:multicollinearity 5896:{\displaystyle k} 5650:{\displaystyle k} 5626:{\displaystyle k} 5606:{\displaystyle k} 5504:{\displaystyle k} 5234:{\displaystyle k} 5066:{\displaystyle 0} 5038:{\displaystyle 0} 4933:multicollinearity 4904:{\displaystyle A} 4834: 4792: 4701: 4585: 4543: 4446: 4328: 4294: 4247: 3956: 3908: 3837:orthogonal matrix 3828:{\displaystyle V} 3732: 3710: 3693:estimator. Thus, 3653:{\displaystyle k} 3629:{\displaystyle k} 3609:{\displaystyle k} 3466: 3434: 3410:{\displaystyle k} 3180: 3001:{\displaystyle W} 2981:{\displaystyle k} 2935:{\displaystyle =} 2822:{\displaystyle V} 2802:{\displaystyle k} 2599: 2445:{\displaystyle V} 1552: 1466: 1403:for some unknown 1140:linear regression 1133:Underlying model: 1040:{\displaystyle p} 967:{\displaystyle p} 925:{\displaystyle n} 875:{\displaystyle p} 855:{\displaystyle n} 610:linear regression 519:multicollinearity 435: 434: 88:Binary regression 47:Simple regression 42:Linear regression 9841: 9815: 9787: 9764:Amemiya, Takeshi 9750: 9749: 9739: 9730:(473): 119–137. 9717: 9711: 9710: 9688: 9682: 9681: 9659: 9648: 9634: 9628: 9627: 9597: 9566:Ridge regression 9544: 9542: 9541: 9536: 9534: 9533: 9528: 9522: 9510: 9508: 9507: 9502: 9500: 9499: 9494: 9488: 9476: 9474: 9473: 9468: 9436:machine learning 9432:cross-validation 9378: 9376: 9375: 9370: 9316:feature elements 9296:feature elements 9276:feature elements 9270:and each of its 9248:high-dimensional 9192:and considers a 9178:cross-validation 9175: 9173: 9172: 9167: 9131: 9129: 9128: 9123: 9087: 9085: 9084: 9079: 9060: 9058: 9057: 9052: 9040: 9038: 9037: 9032: 8996: 8994: 8993: 8988: 8973: 8971: 8970: 8965: 8940: 8938: 8937: 8932: 8930: 8906:ridge regression 8902:shrinkage effect 8899: 8897: 8896: 8891: 8889: 8884: 8883: 8878: 8865: 8863: 8862: 8857: 8855: 8850: 8849: 8844: 8807:cross-validation 8804: 8802: 8801: 8796: 8794: 8789: 8788: 8783: 8767: 8765: 8764: 8759: 8757: 8745: 8743: 8742: 8737: 8735: 8734: 8718: 8716: 8715: 8710: 8705: 8700: 8699: 8694: 8688: 8680: 8679: 8661: 8660: 8644: 8642: 8641: 8636: 8634: 8633: 8614: 8612: 8611: 8606: 8604: 8585: 8583: 8582: 8577: 8566:, especially if 8565: 8563: 8562: 8557: 8546: 8545: 8540: 8539: 8531: 8512: 8511: 8510: 8498: 8497: 8489: 8466: 8464: 8463: 8458: 8444: 8443: 8438: 8437: 8429: 8410: 8409: 8408: 8396: 8395: 8387: 8330: 8328: 8327: 8322: 8320: 8304: 8302: 8301: 8296: 8294: 8293: 8288: 8287: 8279: 8268: 8266: 8265: 8260: 8258: 8250: 8244: 8239: 8178: 8176: 8175: 8170: 8168: 8167: 8166: 8154: 8153: 8145: 8126: 8124: 8123: 8118: 8116: 8115: 8110: 8109: 8101: 8086: 8084: 8083: 8078: 8076: 8075: 8074: 8062: 8061: 8053: 8042: 8040: 8039: 8034: 8032: 8017:would be a more 8016: 8014: 8013: 8008: 8006: 8005: 8000: 7999: 7991: 7980: 7978: 7977: 7972: 7957: 7955: 7954: 7949: 7938: 7937: 7932: 7931: 7923: 7904: 7903: 7902: 7890: 7889: 7881: 7855: 7853: 7852: 7847: 7833: 7832: 7827: 7826: 7818: 7799: 7798: 7797: 7785: 7784: 7776: 7716: 7714: 7713: 7708: 7700: 7699: 7694: 7693: 7685: 7666: 7665: 7660: 7659: 7651: 7628: 7626: 7625: 7620: 7618: 7602: 7600: 7599: 7594: 7592: 7591: 7586: 7585: 7577: 7566: 7564: 7563: 7558: 7556: 7548: 7542: 7537: 7509: 7507: 7506: 7501: 7458: 7456: 7455: 7450: 7442: 7441: 7440: 7428: 7427: 7419: 7400: 7399: 7398: 7386: 7385: 7377: 7354: 7352: 7351: 7346: 7344: 7320: 7318: 7317: 7312: 7300: 7298: 7297: 7292: 7290: 7289: 7284: 7283: 7275: 7264: 7262: 7261: 7256: 7254: 7253: 7252: 7251: 7241: 7240: 7232: 7218: 7216: 7215: 7210: 7205: 7201: 7199: 7195: 7186: 7167: 7163: 7154: 7124: 7120: 7111: 7077: 7075: 7074: 7069: 7063: 7059: 7050: 7029: 7028: 7003: 6998: 6967: 6965: 6964: 6959: 6957: 6956: 6951: 6950: 6942: 6931: 6929: 6928: 6923: 6921: 6920: 6889: 6887: 6886: 6881: 6876: 6868: 6867: 6862: 6855: 6850: 6828: 6825: 6822: 6821: 6812: 6811: 6806: 6800: 6792: 6783: 6782: 6781: 6776: 6767: 6766: 6761: 6741: 6740: 6735: 6734: 6726: 6712: 6710: 6709: 6704: 6702: 6701: 6696: 6695: 6687: 6673: 6671: 6670: 6665: 6641: 6639: 6638: 6633: 6603: 6601: 6600: 6595: 6593: 6592: 6561: 6559: 6558: 6553: 6551: 6543: 6542: 6537: 6530: 6525: 6503: 6500: 6497: 6496: 6487: 6486: 6481: 6475: 6467: 6458: 6457: 6456: 6451: 6442: 6441: 6436: 6392: 6390: 6389: 6384: 6379: 6378: 6355: 6351: 6350: 6349: 6344: 6329: 6328: 6317: 6302: 6301: 6267: 6265: 6264: 6259: 6254: 6246: 6245: 6240: 6233: 6228: 6194: 6192: 6191: 6186: 6178: 6177: 6172: 6157: 6156: 6145: 6133: 6132: 6127: 6120: 6117: 6114: 6113: 6108: 6104: 6103: 6102: 6097: 6091: 6083: 6071: 6070: 6069: 6064: 6055: 6054: 6049: 6024: 6022: 6021: 6016: 6014: 6013: 6008: 6007: 5999: 5988: 5986: 5985: 5980: 5940: 5938: 5937: 5932: 5930: 5925: 5924: 5919: 5902: 5900: 5899: 5894: 5875: 5873: 5872: 5867: 5865: 5864: 5823: 5822: 5812: 5807: 5775: 5774: 5769: 5765: 5763: 5758: 5753: 5747: 5746: 5734: 5733: 5728: 5715: 5710: 5678: 5676: 5675: 5670: 5668: 5656: 5654: 5653: 5648: 5632: 5630: 5629: 5624: 5612: 5610: 5609: 5604: 5592: 5590: 5589: 5584: 5579: 5578: 5573: 5566: 5561: 5548: 5543: 5538: 5529: 5528: 5523: 5510: 5508: 5507: 5502: 5490: 5488: 5487: 5482: 5477: 5476: 5464: 5463: 5448:is minimized at 5444: 5442: 5441: 5436: 5434: 5433: 5428: 5424: 5423: 5422: 5417: 5411: 5410: 5398: 5397: 5392: 5379: 5374: 5346: 5344: 5343: 5338: 5315: 5314: 5309: 5300: 5299: 5294: 5281: 5279: 5278: 5273: 5271: 5270: 5265: 5259: 5258: 5240: 5238: 5237: 5232: 5217: 5215: 5214: 5209: 5207: 5206: 5201: 5184: 5182: 5181: 5176: 5137: 5135: 5134: 5129: 5111: 5109: 5108: 5103: 5101: 5100: 5072: 5070: 5069: 5064: 5047:inflation effect 5044: 5042: 5041: 5036: 5024: 5022: 5021: 5016: 5014: 5009: 5008: 5003: 4987:tends to become 4986: 4984: 4983: 4978: 4976: 4960: 4958: 4957: 4952: 4950: 4910: 4908: 4907: 4902: 4890: 4888: 4887: 4882: 4861: 4859: 4858: 4853: 4842: 4841: 4836: 4835: 4827: 4808: 4807: 4806: 4794: 4793: 4785: 4762: 4760: 4759: 4754: 4715: 4713: 4712: 4707: 4702: 4700: 4699: 4690: 4688: 4683: 4678: 4672: 4671: 4666: 4659: 4653: 4648: 4631: 4630: 4624: 4623: 4621: 4609: 4608: 4593: 4592: 4587: 4586: 4578: 4559: 4558: 4557: 4545: 4544: 4536: 4513: 4511: 4510: 4505: 4460: 4458: 4457: 4452: 4447: 4445: 4444: 4435: 4433: 4428: 4423: 4417: 4416: 4411: 4404: 4398: 4393: 4382: 4381: 4375: 4374: 4372: 4360: 4359: 4344: 4343: 4342: 4330: 4329: 4321: 4302: 4301: 4296: 4295: 4287: 4261: 4259: 4258: 4253: 4248: 4246: 4245: 4236: 4234: 4229: 4224: 4218: 4217: 4212: 4205: 4199: 4194: 4183: 4182: 4176: 4175: 4173: 4161: 4160: 4147: 4142: 4133: 4129: 4127: 4119: 4100: 4092: 4071: 4070: 4060: 4059: 4046: 4041: 4032: 4031: 4019: 4018: 4008: 4003: 3991: 3990: 3980: 3979: 3964: 3963: 3958: 3957: 3949: 3926: 3924: 3923: 3918: 3916: 3915: 3910: 3909: 3901: 3890: 3888: 3887: 3882: 3834: 3832: 3831: 3826: 3814: 3812: 3811: 3806: 3801: 3793: 3792: 3783: 3775: 3774: 3758: 3756: 3755: 3750: 3748: 3747: 3746: 3734: 3733: 3725: 3718: 3717: 3712: 3711: 3703: 3688: 3686: 3685: 3680: 3659: 3657: 3656: 3651: 3635: 3633: 3632: 3627: 3615: 3613: 3612: 3607: 3587: 3585: 3584: 3579: 3544:columns for any 3539: 3537: 3536: 3531: 3529: 3528: 3499: 3497: 3496: 3491: 3489: 3488: 3483: 3474: 3473: 3468: 3467: 3459: 3455: 3454: 3442: 3441: 3436: 3435: 3427: 3416: 3414: 3413: 3408: 3396: 3394: 3393: 3388: 3386: 3374: 3372: 3371: 3366: 3331:. Then, for any 3330: 3328: 3327: 3322: 3320: 3319: 3303: 3301: 3300: 3295: 3293: 3277: 3275: 3274: 3269: 3267: 3266: 3261: 3252: 3246: 3241: 3232: 3231: 3219: 3218: 3208: 3203: 3188: 3187: 3182: 3181: 3173: 3156: 3154: 3153: 3148: 3124: 3123: 3118: 3109: 3108: 3103: 3090: 3088: 3087: 3082: 3080: 3079: 3074: 3065: 3064: 3059: 3052: 3047: 3034: 3029: 3024: 3007: 3005: 3004: 2999: 2987: 2985: 2984: 2979: 2967: 2965: 2964: 2959: 2941: 2939: 2938: 2933: 2928: 2927: 2922: 2916: 2902: 2901: 2896: 2890: 2873: 2871: 2870: 2865: 2863: 2862: 2853: 2845: 2844: 2828: 2826: 2825: 2820: 2808: 2806: 2805: 2800: 2788: 2786: 2785: 2780: 2762: 2760: 2759: 2754: 2752: 2751: 2735: 2733: 2732: 2727: 2685: 2683: 2682: 2677: 2641: 2639: 2638: 2633: 2631: 2630: 2611: 2609: 2608: 2603: 2601: 2600: 2597: 2577: 2575: 2574: 2569: 2567: 2566: 2544: 2542: 2541: 2536: 2534: 2533: 2514: 2512: 2511: 2506: 2504: 2503: 2498: 2485: 2483: 2482: 2477: 2475: 2474: 2469: 2463: 2451: 2449: 2448: 2443: 2431: 2429: 2428: 2423: 2421: 2416: 2415: 2410: 2396:principal values 2393: 2391: 2390: 2385: 2377: 2376: 2358: 2357: 2341: 2339: 2338: 2333: 2331: 2330: 2318: 2314: 2312: 2307: 2288: 2283: 2260: 2256: 2255: 2254: 2236: 2235: 2212: 2211: 2189: 2187: 2186: 2181: 2179: 2174: 2173: 2168: 2151: 2149: 2148: 2143: 2141: 2140: 2113: 2111: 2110: 2105: 2103: 2086:orthonormal sets 2083: 2081: 2080: 2075: 2070: 2069: 2064: 2049: 2048: 2043: 2031: 2030: 2008: 2006: 2005: 2000: 1995: 1994: 1989: 1974: 1973: 1968: 1956: 1955: 1929: 1927: 1926: 1921: 1919: 1903: 1901: 1900: 1895: 1887: 1886: 1868: 1867: 1851: 1849: 1848: 1843: 1841: 1837: 1836: 1835: 1817: 1816: 1793: 1792: 1770: 1768: 1767: 1762: 1760: 1744: 1742: 1741: 1736: 1734: 1733: 1715: 1704:. For this, let 1703: 1701: 1700: 1695: 1693: 1675: 1673: 1672: 1667: 1665: 1653: 1651: 1650: 1645: 1643: 1631: 1629: 1628: 1623: 1621: 1616: 1615: 1610: 1604: 1603: 1591: 1586: 1585: 1580: 1568: 1567: 1566: 1554: 1553: 1545: 1529:full column rank 1526: 1524: 1523: 1518: 1516: 1500: 1498: 1497: 1492: 1490: 1478: 1476: 1475: 1470: 1468: 1467: 1459: 1441: 1439: 1438: 1433: 1423: 1422: 1402: 1400: 1399: 1394: 1392: 1391: 1376: 1375: 1363: 1359: 1336: 1334: 1333: 1328: 1325: 1317: 1313: 1291: 1289: 1288: 1283: 1281: 1269: 1267: 1266: 1261: 1259: 1258: 1253: 1244: 1232: 1230: 1229: 1224: 1218: 1210: 1205: 1197: 1185: 1183: 1182: 1177: 1175: 1163: 1161: 1160: 1155: 1153: 1123:PCA is sensitive 1120: 1118: 1117: 1112: 1110: 1098: 1096: 1095: 1090: 1088: 1068: 1066: 1065: 1060: 1058: 1046: 1044: 1043: 1038: 1027:and each of the 1026: 1024: 1023: 1018: 1016: 998: 996: 995: 990: 988: 973: 971: 970: 965: 953: 951: 950: 945: 943: 931: 929: 928: 923: 911: 909: 908: 903: 881: 879: 878: 873: 861: 859: 858: 853: 837: 835: 834: 829: 827: 826: 821: 817: 816: 815: 810: 795: 794: 789: 774: 773: 762: 749: 747: 746: 741: 739: 738: 733: 729: 728: 727: 709: 708: 690: 689: 678: 641: 639: 638: 633: 603: 601: 600: 595: 574:on the observed 569: 567: 566: 561: 427: 420: 413: 397: 396: 304:Ridge regression 139:Multilevel model 19: 18: 9849: 9848: 9844: 9843: 9842: 9840: 9839: 9838: 9834:Factor analysis 9819: 9818: 9812: 9784: 9759: 9757:Further reading 9754: 9753: 9737:10.1.1.516.2313 9718: 9714: 9689: 9685: 9678:10.2307/1267793 9660: 9651: 9635: 9631: 9616:10.2307/2348005 9598: 9594: 9589: 9552: 9529: 9524: 9523: 9518: 9516: 9513: 9512: 9495: 9490: 9489: 9484: 9482: 9479: 9478: 9456: 9453: 9452: 9358: 9355: 9354: 9351:kernel function 9260:kernel function 9229:kernel function 9186: 9137: 9134: 9133: 9093: 9090: 9089: 9067: 9064: 9063: 9046: 9043: 9042: 9002: 8999: 8998: 8982: 8979: 8978: 8959: 8956: 8955: 8926: 8924: 8921: 8920: 8885: 8879: 8874: 8873: 8871: 8868: 8867: 8851: 8845: 8840: 8839: 8837: 8834: 8833: 8826: 8814: 8790: 8784: 8779: 8778: 8776: 8773: 8772: 8753: 8751: 8748: 8747: 8730: 8726: 8724: 8721: 8720: 8701: 8695: 8690: 8689: 8684: 8675: 8671: 8656: 8652: 8650: 8647: 8646: 8626: 8622: 8620: 8617: 8616: 8600: 8598: 8595: 8594: 8571: 8568: 8567: 8541: 8530: 8529: 8528: 8500: 8499: 8488: 8487: 8486: 8475: 8472: 8471: 8439: 8428: 8427: 8426: 8398: 8397: 8386: 8385: 8384: 8339: 8336: 8335: 8316: 8314: 8311: 8310: 8289: 8278: 8277: 8276: 8274: 8271: 8270: 8254: 8246: 8240: 8223: 8187: 8184: 8183: 8156: 8155: 8144: 8143: 8142: 8140: 8137: 8136: 8111: 8100: 8099: 8098: 8096: 8093: 8092: 8064: 8063: 8052: 8051: 8050: 8048: 8045: 8044: 8028: 8026: 8023: 8022: 8001: 7990: 7989: 7988: 7986: 7983: 7982: 7966: 7963: 7962: 7933: 7922: 7921: 7920: 7892: 7891: 7880: 7879: 7878: 7867: 7864: 7863: 7828: 7817: 7816: 7815: 7787: 7786: 7775: 7774: 7773: 7728: 7725: 7724: 7695: 7684: 7683: 7682: 7661: 7650: 7649: 7648: 7637: 7634: 7633: 7629:and therefore 7614: 7612: 7609: 7608: 7587: 7576: 7575: 7574: 7572: 7569: 7568: 7552: 7544: 7538: 7521: 7515: 7512: 7511: 7471: 7468: 7467: 7430: 7429: 7418: 7417: 7416: 7388: 7387: 7376: 7375: 7374: 7363: 7360: 7359: 7340: 7338: 7335: 7334: 7327: 7306: 7303: 7302: 7285: 7274: 7273: 7272: 7270: 7267: 7266: 7247: 7243: 7242: 7231: 7230: 7229: 7227: 7224: 7223: 7191: 7187: 7182: 7159: 7155: 7144: 7139: 7135: 7116: 7112: 7095: 7089: 7086: 7085: 7055: 7051: 7034: 7012: 7008: 6999: 6982: 6976: 6973: 6972: 6952: 6941: 6940: 6939: 6937: 6934: 6933: 6904: 6900: 6898: 6895: 6894: 6872: 6863: 6858: 6857: 6851: 6834: 6824: 6817: 6813: 6807: 6802: 6801: 6796: 6788: 6777: 6772: 6771: 6762: 6757: 6756: 6755: 6736: 6725: 6724: 6723: 6721: 6718: 6717: 6697: 6686: 6685: 6684: 6682: 6679: 6678: 6647: 6644: 6643: 6609: 6606: 6605: 6576: 6572: 6570: 6567: 6566: 6547: 6538: 6533: 6532: 6526: 6509: 6499: 6492: 6488: 6482: 6477: 6476: 6471: 6463: 6452: 6447: 6446: 6437: 6432: 6431: 6430: 6424: 6421: 6420: 6414: 6356: 6345: 6340: 6339: 6318: 6313: 6312: 6311: 6307: 6306: 6285: 6281: 6279: 6276: 6275: 6250: 6241: 6236: 6235: 6229: 6212: 6206: 6203: 6202: 6173: 6168: 6167: 6146: 6141: 6140: 6128: 6123: 6122: 6116: 6109: 6098: 6093: 6092: 6087: 6079: 6078: 6074: 6073: 6065: 6060: 6059: 6050: 6045: 6044: 6043: 6037: 6034: 6033: 6009: 5998: 5997: 5996: 5994: 5991: 5990: 5962: 5959: 5958: 5951: 5926: 5920: 5915: 5914: 5912: 5909: 5908: 5888: 5885: 5884: 5860: 5859: 5848: 5842: 5841: 5824: 5818: 5814: 5808: 5791: 5780: 5779: 5770: 5759: 5754: 5749: 5742: 5738: 5729: 5724: 5723: 5722: 5718: 5717: 5711: 5700: 5694: 5691: 5690: 5664: 5662: 5659: 5658: 5642: 5639: 5638: 5618: 5615: 5614: 5598: 5595: 5594: 5574: 5569: 5568: 5562: 5557: 5544: 5539: 5534: 5524: 5519: 5518: 5516: 5513: 5512: 5496: 5493: 5492: 5472: 5468: 5459: 5455: 5453: 5450: 5449: 5429: 5418: 5413: 5412: 5406: 5402: 5393: 5388: 5387: 5386: 5382: 5381: 5375: 5364: 5358: 5355: 5354: 5310: 5305: 5304: 5295: 5290: 5289: 5287: 5284: 5283: 5266: 5261: 5260: 5254: 5250: 5248: 5245: 5244: 5226: 5223: 5222: 5202: 5197: 5196: 5194: 5191: 5190: 5143: 5140: 5139: 5117: 5114: 5113: 5096: 5092: 5090: 5087: 5086: 5079: 5058: 5055: 5054: 5030: 5027: 5026: 5010: 5004: 4999: 4998: 4996: 4993: 4992: 4972: 4970: 4967: 4966: 4965:and therefore, 4946: 4944: 4941: 4940: 4929: 4896: 4893: 4892: 4870: 4867: 4866: 4837: 4826: 4825: 4824: 4796: 4795: 4784: 4783: 4782: 4771: 4768: 4767: 4724: 4721: 4720: 4695: 4691: 4684: 4679: 4674: 4667: 4662: 4661: 4660: 4658: 4649: 4632: 4626: 4615: 4613: 4612: 4611: 4604: 4600: 4588: 4577: 4576: 4575: 4547: 4546: 4535: 4534: 4533: 4522: 4519: 4518: 4469: 4466: 4465: 4440: 4436: 4429: 4424: 4419: 4412: 4407: 4406: 4405: 4403: 4394: 4383: 4377: 4366: 4364: 4363: 4362: 4355: 4351: 4332: 4331: 4320: 4319: 4318: 4297: 4286: 4285: 4284: 4273: 4270: 4269: 4265:In particular: 4241: 4237: 4230: 4225: 4220: 4213: 4208: 4207: 4206: 4204: 4195: 4184: 4178: 4167: 4165: 4164: 4163: 4156: 4152: 4143: 4138: 4120: 4115: 4093: 4088: 4083: 4079: 4066: 4062: 4055: 4051: 4042: 4037: 4024: 4020: 4014: 4010: 4004: 3999: 3986: 3982: 3975: 3971: 3959: 3948: 3947: 3946: 3935: 3932: 3931: 3911: 3900: 3899: 3898: 3896: 3893: 3892: 3852: 3849: 3848: 3845: 3820: 3817: 3816: 3797: 3788: 3784: 3779: 3770: 3766: 3764: 3761: 3760: 3736: 3735: 3724: 3723: 3722: 3713: 3702: 3701: 3700: 3698: 3695: 3694: 3668: 3665: 3664: 3645: 3642: 3641: 3621: 3618: 3617: 3601: 3598: 3597: 3596:jointly on the 3549: 3546: 3545: 3524: 3520: 3518: 3515: 3514: 3511: 3506: 3484: 3479: 3478: 3469: 3458: 3457: 3456: 3450: 3446: 3437: 3426: 3425: 3424: 3422: 3419: 3418: 3402: 3399: 3398: 3382: 3380: 3377: 3376: 3336: 3333: 3332: 3315: 3311: 3309: 3306: 3305: 3289: 3287: 3284: 3283: 3262: 3257: 3256: 3248: 3242: 3237: 3224: 3220: 3214: 3210: 3204: 3199: 3183: 3172: 3171: 3170: 3168: 3165: 3164: 3119: 3114: 3113: 3104: 3099: 3098: 3096: 3093: 3092: 3075: 3070: 3069: 3060: 3055: 3054: 3048: 3043: 3030: 3025: 3020: 3017: 3014: 3013: 2993: 2990: 2989: 2973: 2970: 2969: 2947: 2944: 2943: 2923: 2918: 2917: 2912: 2897: 2892: 2891: 2886: 2878: 2875: 2874: 2858: 2854: 2849: 2840: 2836: 2834: 2831: 2830: 2814: 2811: 2810: 2794: 2791: 2790: 2768: 2765: 2764: 2747: 2743: 2741: 2738: 2737: 2697: 2694: 2693: 2647: 2644: 2643: 2626: 2622: 2620: 2617: 2616: 2614:principal value 2596: 2592: 2590: 2587: 2586: 2559: 2555: 2553: 2550: 2549: 2526: 2522: 2520: 2517: 2516: 2499: 2494: 2493: 2491: 2488: 2487: 2470: 2465: 2464: 2459: 2457: 2454: 2453: 2437: 2434: 2433: 2417: 2411: 2406: 2405: 2403: 2400: 2399: 2372: 2368: 2353: 2349: 2347: 2344: 2343: 2326: 2322: 2308: 2303: 2284: 2279: 2274: 2270: 2250: 2246: 2231: 2227: 2226: 2222: 2201: 2197: 2195: 2192: 2191: 2175: 2169: 2164: 2163: 2161: 2158: 2157: 2136: 2132: 2124: 2121: 2120: 2099: 2097: 2094: 2093: 2065: 2060: 2059: 2044: 2039: 2038: 2020: 2016: 2014: 2011: 2010: 1990: 1985: 1984: 1969: 1964: 1963: 1945: 1941: 1939: 1936: 1935: 1915: 1913: 1910: 1909: 1906:singular values 1882: 1878: 1863: 1859: 1857: 1854: 1853: 1831: 1827: 1812: 1808: 1807: 1803: 1782: 1778: 1776: 1773: 1772: 1756: 1754: 1751: 1750: 1729: 1725: 1711: 1709: 1706: 1705: 1689: 1687: 1684: 1683: 1661: 1659: 1656: 1655: 1639: 1637: 1634: 1633: 1617: 1611: 1606: 1605: 1596: 1592: 1587: 1581: 1576: 1575: 1556: 1555: 1544: 1543: 1542: 1540: 1537: 1536: 1512: 1510: 1507: 1506: 1486: 1484: 1481: 1480: 1458: 1457: 1455: 1452: 1451: 1418: 1414: 1412: 1409: 1408: 1381: 1377: 1371: 1367: 1355: 1351: 1342: 1339: 1338: 1321: 1309: 1305: 1297: 1294: 1293: 1277: 1275: 1272: 1271: 1254: 1249: 1248: 1240: 1238: 1235: 1234: 1214: 1206: 1201: 1193: 1191: 1188: 1187: 1171: 1169: 1166: 1165: 1149: 1147: 1144: 1143: 1106: 1104: 1101: 1100: 1084: 1082: 1079: 1078: 1075:empirical means 1054: 1052: 1049: 1048: 1032: 1029: 1028: 1012: 1010: 1007: 1006: 984: 982: 979: 978: 959: 956: 955: 939: 937: 934: 933: 917: 914: 913: 891: 888: 887: 867: 864: 863: 847: 844: 843: 822: 811: 806: 805: 790: 785: 784: 783: 779: 778: 763: 758: 757: 755: 752: 751: 734: 723: 719: 704: 700: 699: 695: 694: 679: 674: 673: 671: 668: 667: 661: 628: 625: 624: 590: 587: 586: 556: 553: 552: 543: 431: 391: 371:Goodness of fit 78:Discrete choice 17: 12: 11: 5: 9847: 9837: 9836: 9831: 9817: 9816: 9810: 9788: 9782: 9758: 9755: 9752: 9751: 9712: 9701:(2): 109–135. 9683: 9672:(3): 289–295. 9649: 9629: 9610:(3): 300–303. 9591: 9590: 9588: 9585: 9584: 9583: 9578: 9573: 9568: 9563: 9558: 9551: 9548: 9532: 9527: 9521: 9498: 9493: 9487: 9477:kernel matrix 9466: 9463: 9460: 9388:kernel machine 9368: 9365: 9362: 9347:inner products 9343:inner products 9304:kernel machine 9240:kernel machine 9198:kernel machine 9185: 9182: 9165: 9162: 9159: 9156: 9153: 9150: 9147: 9144: 9141: 9121: 9118: 9115: 9112: 9109: 9106: 9103: 9100: 9097: 9077: 9074: 9071: 9050: 9030: 9027: 9024: 9021: 9018: 9015: 9012: 9009: 9006: 8986: 8963: 8951:supervised PCR 8929: 8888: 8882: 8877: 8854: 8848: 8843: 8825: 8822: 8812: 8793: 8787: 8782: 8756: 8733: 8729: 8708: 8704: 8698: 8693: 8687: 8683: 8678: 8674: 8670: 8667: 8664: 8659: 8655: 8632: 8629: 8625: 8603: 8575: 8555: 8552: 8549: 8544: 8537: 8534: 8527: 8524: 8521: 8518: 8515: 8509: 8506: 8503: 8495: 8492: 8485: 8482: 8479: 8468: 8467: 8456: 8453: 8450: 8447: 8442: 8435: 8432: 8425: 8422: 8419: 8416: 8413: 8407: 8404: 8401: 8393: 8390: 8383: 8380: 8377: 8373: 8370: 8367: 8364: 8361: 8358: 8355: 8352: 8349: 8346: 8343: 8319: 8292: 8285: 8282: 8257: 8253: 8249: 8243: 8238: 8235: 8232: 8229: 8226: 8222: 8218: 8215: 8212: 8209: 8206: 8203: 8200: 8197: 8194: 8191: 8165: 8162: 8159: 8151: 8148: 8114: 8107: 8104: 8073: 8070: 8067: 8059: 8056: 8031: 8004: 7997: 7994: 7970: 7959: 7958: 7947: 7944: 7941: 7936: 7929: 7926: 7919: 7916: 7913: 7910: 7907: 7901: 7898: 7895: 7887: 7884: 7877: 7874: 7871: 7857: 7856: 7845: 7842: 7839: 7836: 7831: 7824: 7821: 7814: 7811: 7808: 7805: 7802: 7796: 7793: 7790: 7782: 7779: 7772: 7769: 7766: 7762: 7759: 7756: 7753: 7750: 7747: 7744: 7741: 7738: 7735: 7732: 7718: 7717: 7706: 7703: 7698: 7691: 7688: 7681: 7678: 7675: 7672: 7669: 7664: 7657: 7654: 7647: 7644: 7641: 7617: 7590: 7583: 7580: 7555: 7551: 7547: 7541: 7536: 7533: 7530: 7527: 7524: 7520: 7499: 7496: 7493: 7490: 7487: 7484: 7481: 7478: 7475: 7460: 7459: 7448: 7445: 7439: 7436: 7433: 7425: 7422: 7415: 7412: 7409: 7406: 7403: 7397: 7394: 7391: 7383: 7380: 7373: 7370: 7367: 7343: 7326: 7323: 7310: 7288: 7281: 7278: 7250: 7246: 7238: 7235: 7220: 7219: 7208: 7204: 7198: 7194: 7190: 7185: 7181: 7177: 7174: 7171: 7166: 7162: 7158: 7153: 7150: 7147: 7143: 7138: 7134: 7131: 7128: 7123: 7119: 7115: 7110: 7107: 7104: 7101: 7098: 7094: 7079: 7078: 7067: 7062: 7058: 7054: 7049: 7046: 7043: 7040: 7037: 7033: 7027: 7024: 7021: 7018: 7015: 7011: 7007: 7002: 6997: 6994: 6991: 6988: 6985: 6981: 6955: 6948: 6945: 6919: 6916: 6913: 6910: 6907: 6903: 6891: 6890: 6879: 6875: 6871: 6866: 6861: 6854: 6849: 6846: 6843: 6840: 6837: 6833: 6820: 6816: 6810: 6805: 6799: 6795: 6791: 6787: 6780: 6775: 6770: 6765: 6760: 6754: 6750: 6747: 6744: 6739: 6732: 6729: 6700: 6693: 6690: 6663: 6660: 6657: 6654: 6651: 6631: 6628: 6625: 6622: 6619: 6616: 6613: 6591: 6588: 6585: 6582: 6579: 6575: 6563: 6562: 6550: 6546: 6541: 6536: 6529: 6524: 6521: 6518: 6515: 6512: 6508: 6495: 6491: 6485: 6480: 6474: 6470: 6466: 6462: 6455: 6450: 6445: 6440: 6435: 6429: 6413: 6410: 6398:regularization 6394: 6393: 6382: 6377: 6374: 6371: 6368: 6365: 6362: 6359: 6354: 6348: 6343: 6338: 6335: 6332: 6327: 6324: 6321: 6316: 6310: 6305: 6300: 6297: 6294: 6291: 6288: 6284: 6269: 6268: 6257: 6253: 6249: 6244: 6239: 6232: 6227: 6224: 6221: 6218: 6215: 6211: 6196: 6195: 6184: 6181: 6176: 6171: 6166: 6163: 6160: 6155: 6152: 6149: 6144: 6139: 6136: 6131: 6126: 6112: 6107: 6101: 6096: 6090: 6086: 6082: 6077: 6068: 6063: 6058: 6053: 6048: 6042: 6012: 6005: 6002: 5978: 5975: 5972: 5969: 5966: 5950: 5947: 5929: 5923: 5918: 5892: 5877: 5876: 5863: 5858: 5855: 5852: 5849: 5847: 5844: 5843: 5840: 5837: 5834: 5831: 5828: 5825: 5821: 5817: 5811: 5806: 5803: 5800: 5797: 5794: 5790: 5786: 5785: 5783: 5778: 5773: 5768: 5762: 5757: 5752: 5745: 5741: 5737: 5732: 5727: 5721: 5714: 5709: 5706: 5703: 5699: 5686:is given by: 5667: 5646: 5622: 5602: 5582: 5577: 5572: 5565: 5560: 5556: 5552: 5547: 5542: 5537: 5532: 5527: 5522: 5500: 5480: 5475: 5471: 5467: 5462: 5458: 5446: 5445: 5432: 5427: 5421: 5416: 5409: 5405: 5401: 5396: 5391: 5385: 5378: 5373: 5370: 5367: 5363: 5336: 5333: 5330: 5327: 5324: 5321: 5318: 5313: 5308: 5303: 5298: 5293: 5269: 5264: 5257: 5253: 5230: 5205: 5200: 5174: 5171: 5168: 5165: 5162: 5159: 5156: 5153: 5150: 5147: 5127: 5124: 5121: 5099: 5095: 5078: 5075: 5062: 5034: 5013: 5007: 5002: 4989:rank deficient 4975: 4949: 4928: 4925: 4900: 4880: 4877: 4874: 4863: 4862: 4851: 4848: 4845: 4840: 4833: 4830: 4823: 4820: 4817: 4814: 4811: 4805: 4802: 4799: 4791: 4788: 4781: 4778: 4775: 4752: 4749: 4746: 4743: 4740: 4737: 4734: 4731: 4728: 4719:Thus, for all 4717: 4716: 4705: 4698: 4694: 4687: 4682: 4677: 4670: 4665: 4657: 4652: 4647: 4644: 4641: 4638: 4635: 4629: 4619: 4607: 4603: 4599: 4596: 4591: 4584: 4581: 4574: 4571: 4568: 4565: 4562: 4556: 4553: 4550: 4542: 4539: 4532: 4529: 4526: 4503: 4500: 4497: 4494: 4491: 4488: 4485: 4482: 4479: 4476: 4473: 4464:Hence for all 4462: 4461: 4450: 4443: 4439: 4432: 4427: 4422: 4415: 4410: 4402: 4397: 4392: 4389: 4386: 4380: 4370: 4358: 4354: 4350: 4347: 4341: 4338: 4335: 4327: 4324: 4317: 4314: 4311: 4308: 4305: 4300: 4293: 4290: 4283: 4280: 4277: 4263: 4262: 4251: 4244: 4240: 4233: 4228: 4223: 4216: 4211: 4203: 4198: 4193: 4190: 4187: 4181: 4171: 4159: 4155: 4151: 4146: 4141: 4137: 4132: 4126: 4123: 4118: 4114: 4110: 4107: 4104: 4099: 4096: 4091: 4087: 4082: 4078: 4075: 4069: 4065: 4058: 4054: 4050: 4045: 4040: 4036: 4030: 4027: 4023: 4017: 4013: 4007: 4002: 3998: 3994: 3989: 3985: 3978: 3974: 3970: 3967: 3962: 3955: 3952: 3945: 3942: 3939: 3914: 3907: 3904: 3880: 3877: 3874: 3871: 3868: 3865: 3862: 3859: 3856: 3844: 3841: 3824: 3804: 3800: 3796: 3791: 3787: 3782: 3778: 3773: 3769: 3745: 3742: 3739: 3731: 3728: 3721: 3716: 3709: 3706: 3678: 3675: 3672: 3649: 3625: 3605: 3577: 3574: 3571: 3568: 3565: 3562: 3559: 3556: 3553: 3527: 3523: 3510: 3507: 3505: 3502: 3487: 3482: 3477: 3472: 3465: 3462: 3453: 3449: 3445: 3440: 3433: 3430: 3406: 3385: 3364: 3361: 3358: 3355: 3352: 3349: 3346: 3343: 3340: 3318: 3314: 3292: 3265: 3260: 3255: 3251: 3245: 3240: 3236: 3230: 3227: 3223: 3217: 3213: 3207: 3202: 3198: 3194: 3191: 3186: 3179: 3176: 3146: 3143: 3140: 3137: 3134: 3129: 3122: 3117: 3112: 3107: 3102: 3078: 3073: 3068: 3063: 3058: 3051: 3046: 3042: 3038: 3033: 3028: 3023: 2997: 2977: 2957: 2954: 2951: 2931: 2926: 2921: 2915: 2911: 2908: 2905: 2900: 2895: 2889: 2885: 2882: 2861: 2857: 2852: 2848: 2843: 2839: 2818: 2798: 2778: 2775: 2772: 2750: 2746: 2725: 2722: 2719: 2716: 2713: 2710: 2707: 2704: 2701: 2675: 2672: 2669: 2666: 2663: 2660: 2657: 2654: 2651: 2629: 2625: 2595: 2565: 2562: 2558: 2532: 2529: 2525: 2502: 2497: 2473: 2468: 2462: 2441: 2420: 2414: 2409: 2383: 2380: 2375: 2371: 2367: 2364: 2361: 2356: 2352: 2329: 2325: 2321: 2317: 2311: 2306: 2302: 2298: 2295: 2292: 2287: 2282: 2278: 2273: 2269: 2266: 2263: 2259: 2253: 2249: 2245: 2242: 2239: 2234: 2230: 2225: 2221: 2218: 2215: 2210: 2207: 2204: 2200: 2178: 2172: 2167: 2139: 2135: 2131: 2128: 2114:respectively. 2102: 2073: 2068: 2063: 2058: 2055: 2052: 2047: 2042: 2037: 2034: 2029: 2026: 2023: 2019: 1998: 1993: 1988: 1983: 1980: 1977: 1972: 1967: 1962: 1959: 1954: 1951: 1948: 1944: 1918: 1893: 1890: 1885: 1881: 1877: 1874: 1871: 1866: 1862: 1840: 1834: 1830: 1826: 1823: 1820: 1815: 1811: 1806: 1802: 1799: 1796: 1791: 1788: 1785: 1781: 1759: 1732: 1728: 1724: 1721: 1718: 1714: 1692: 1664: 1642: 1620: 1614: 1609: 1602: 1599: 1595: 1590: 1584: 1579: 1574: 1571: 1565: 1562: 1559: 1551: 1548: 1515: 1489: 1465: 1462: 1429: 1426: 1421: 1417: 1390: 1387: 1384: 1380: 1374: 1370: 1366: 1362: 1358: 1354: 1350: 1347: 1324: 1320: 1316: 1312: 1308: 1304: 1301: 1280: 1257: 1252: 1247: 1243: 1221: 1217: 1213: 1209: 1204: 1200: 1196: 1174: 1152: 1109: 1087: 1057: 1036: 1015: 987: 963: 942: 921: 912:. Each of the 901: 898: 895: 871: 851: 825: 820: 814: 809: 804: 801: 798: 793: 788: 782: 777: 772: 769: 766: 761: 737: 732: 726: 722: 718: 715: 712: 707: 703: 698: 693: 688: 685: 682: 677: 660: 657: 656: 655: 618: 617: 580: 579: 542: 539: 433: 432: 430: 429: 422: 415: 407: 404: 403: 402: 401: 386: 385: 384: 383: 378: 373: 368: 363: 358: 350: 349: 345: 344: 343: 342: 337: 332: 327: 322: 314: 313: 312: 311: 306: 301: 296: 291: 283: 282: 281: 280: 275: 270: 265: 257: 256: 255: 254: 249: 244: 236: 235: 231: 230: 229: 228: 220: 219: 218: 217: 212: 207: 202: 197: 192: 187: 182: 180:Semiparametric 177: 172: 164: 163: 162: 161: 156: 151: 149:Random effects 146: 141: 133: 132: 131: 130: 125: 123:Ordered probit 120: 115: 110: 105: 100: 95: 90: 85: 80: 75: 70: 62: 61: 60: 59: 54: 49: 44: 36: 35: 31: 30: 24: 23: 15: 9: 6: 4: 3: 2: 9846: 9835: 9832: 9830: 9827: 9826: 9824: 9813: 9807: 9803: 9799: 9798: 9793: 9789: 9785: 9779: 9775: 9771: 9770: 9765: 9761: 9760: 9747: 9743: 9738: 9733: 9729: 9725: 9724: 9716: 9708: 9704: 9700: 9696: 9695: 9694:Technometrics 9687: 9679: 9675: 9671: 9667: 9666: 9665:Technometrics 9658: 9656: 9654: 9647: 9646:0-19-920613-9 9643: 9639: 9633: 9625: 9621: 9617: 9613: 9609: 9605: 9604: 9596: 9592: 9582: 9579: 9577: 9574: 9572: 9569: 9567: 9564: 9562: 9559: 9557: 9554: 9553: 9547: 9530: 9496: 9464: 9461: 9458: 9449: 9443: 9441: 9437: 9433: 9429: 9425: 9421: 9417: 9413: 9409: 9405: 9401: 9400:feature space 9397: 9396:kernel matrix 9393: 9389: 9384: 9382: 9381:kernel matrix 9366: 9363: 9360: 9352: 9348: 9344: 9340: 9336: 9335:feature space 9332: 9329:However, the 9327: 9325: 9321: 9317: 9313: 9309: 9305: 9301: 9297: 9293: 9289: 9285: 9281: 9277: 9273: 9269: 9265: 9261: 9257: 9256:feature space 9253: 9250:(potentially 9249: 9245: 9241: 9236: 9234: 9233:linear kernel 9230: 9226: 9222: 9219: 9215: 9211: 9207: 9203: 9199: 9195: 9191: 9190:classical PCA 9181: 9179: 9160: 9157: 9154: 9151: 9148: 9142: 9139: 9116: 9113: 9110: 9107: 9104: 9098: 9095: 9075: 9072: 9069: 9048: 9025: 9022: 9019: 9016: 9013: 9007: 9004: 8984: 8976: 8961: 8952: 8947: 8945: 8918: 8913: 8911: 8907: 8903: 8880: 8846: 8831: 8821: 8819: 8815: 8808: 8785: 8769: 8731: 8727: 8706: 8696: 8685: 8676: 8672: 8668: 8662: 8657: 8653: 8630: 8627: 8623: 8591: 8589: 8573: 8553: 8550: 8542: 8535: 8522: 8519: 8516: 8493: 8480: 8477: 8454: 8451: 8448: 8440: 8433: 8420: 8417: 8414: 8391: 8378: 8375: 8371: 8365: 8362: 8359: 8356: 8353: 8347: 8344: 8334: 8333: 8332: 8308: 8290: 8283: 8251: 8241: 8233: 8230: 8227: 8220: 8216: 8210: 8207: 8204: 8201: 8198: 8192: 8189: 8180: 8149: 8134: 8130: 8112: 8105: 8090: 8057: 8020: 8002: 7995: 7968: 7945: 7942: 7934: 7927: 7914: 7911: 7908: 7885: 7872: 7869: 7862: 7861: 7860: 7843: 7840: 7837: 7829: 7822: 7809: 7806: 7803: 7780: 7767: 7764: 7760: 7754: 7751: 7748: 7745: 7742: 7736: 7733: 7723: 7722: 7721: 7704: 7696: 7689: 7676: 7673: 7670: 7662: 7655: 7642: 7639: 7632: 7631: 7630: 7606: 7588: 7581: 7549: 7539: 7531: 7528: 7525: 7518: 7494: 7491: 7488: 7485: 7482: 7476: 7473: 7465: 7446: 7423: 7410: 7407: 7404: 7381: 7368: 7365: 7358: 7357: 7356: 7332: 7322: 7308: 7286: 7279: 7248: 7244: 7236: 7206: 7202: 7196: 7192: 7188: 7183: 7179: 7175: 7172: 7169: 7164: 7160: 7156: 7151: 7148: 7145: 7141: 7136: 7132: 7129: 7126: 7121: 7117: 7113: 7105: 7102: 7099: 7084: 7083: 7082: 7065: 7060: 7056: 7052: 7044: 7041: 7038: 7022: 7019: 7016: 7009: 7005: 7000: 6992: 6989: 6986: 6979: 6971: 6970: 6969: 6953: 6946: 6914: 6911: 6908: 6901: 6877: 6869: 6864: 6852: 6844: 6841: 6838: 6831: 6818: 6808: 6793: 6778: 6768: 6763: 6748: 6745: 6742: 6737: 6730: 6716: 6715: 6714: 6698: 6691: 6675: 6661: 6658: 6655: 6652: 6649: 6626: 6623: 6620: 6614: 6611: 6586: 6583: 6580: 6573: 6544: 6539: 6527: 6519: 6516: 6513: 6506: 6493: 6483: 6468: 6453: 6443: 6438: 6419: 6418: 6417: 6409: 6407: 6403: 6399: 6380: 6372: 6369: 6366: 6360: 6357: 6352: 6346: 6336: 6333: 6330: 6325: 6322: 6319: 6308: 6303: 6295: 6292: 6289: 6282: 6274: 6273: 6272: 6255: 6247: 6242: 6230: 6222: 6219: 6216: 6209: 6201: 6200: 6199: 6182: 6174: 6164: 6161: 6158: 6153: 6150: 6147: 6134: 6129: 6110: 6099: 6084: 6066: 6056: 6051: 6032: 6031: 6030: 6028: 6010: 6003: 5976: 5973: 5970: 5967: 5964: 5956: 5946: 5944: 5921: 5906: 5890: 5882: 5856: 5853: 5850: 5845: 5838: 5835: 5832: 5829: 5826: 5819: 5815: 5809: 5804: 5801: 5798: 5795: 5792: 5788: 5781: 5776: 5771: 5760: 5755: 5743: 5739: 5735: 5730: 5712: 5707: 5704: 5701: 5697: 5689: 5688: 5687: 5685: 5680: 5644: 5636: 5620: 5600: 5580: 5575: 5563: 5558: 5554: 5550: 5545: 5540: 5530: 5525: 5498: 5478: 5473: 5469: 5465: 5460: 5456: 5430: 5419: 5407: 5403: 5399: 5394: 5376: 5371: 5368: 5365: 5361: 5353: 5352: 5351: 5348: 5331: 5328: 5325: 5322: 5319: 5311: 5301: 5296: 5267: 5255: 5251: 5243: 5228: 5221: 5203: 5188: 5172: 5166: 5163: 5160: 5157: 5154: 5148: 5145: 5125: 5122: 5119: 5097: 5093: 5084: 5074: 5060: 5052: 5051:destabilizing 5048: 5032: 5005: 4990: 4964: 4938: 4934: 4924: 4922: 4918: 4914: 4898: 4878: 4875: 4872: 4849: 4846: 4838: 4831: 4818: 4815: 4812: 4789: 4776: 4773: 4766: 4765: 4764: 4747: 4744: 4741: 4738: 4735: 4729: 4726: 4703: 4696: 4692: 4685: 4680: 4668: 4655: 4650: 4645: 4642: 4639: 4636: 4633: 4617: 4605: 4601: 4597: 4589: 4582: 4569: 4566: 4563: 4540: 4527: 4524: 4517: 4516: 4515: 4498: 4495: 4492: 4489: 4486: 4483: 4480: 4474: 4471: 4448: 4441: 4437: 4430: 4425: 4413: 4400: 4395: 4390: 4387: 4384: 4368: 4356: 4352: 4348: 4325: 4312: 4309: 4306: 4298: 4291: 4278: 4275: 4268: 4267: 4266: 4249: 4242: 4238: 4231: 4226: 4214: 4201: 4196: 4191: 4188: 4185: 4169: 4157: 4153: 4149: 4144: 4139: 4135: 4130: 4124: 4121: 4116: 4112: 4108: 4105: 4102: 4097: 4094: 4089: 4085: 4080: 4076: 4073: 4067: 4063: 4056: 4052: 4048: 4043: 4038: 4034: 4028: 4025: 4015: 4011: 4005: 4000: 3996: 3987: 3983: 3976: 3972: 3968: 3960: 3953: 3940: 3937: 3930: 3929: 3928: 3912: 3905: 3875: 3872: 3869: 3866: 3863: 3857: 3854: 3840: 3838: 3822: 3802: 3794: 3789: 3785: 3776: 3771: 3767: 3729: 3719: 3714: 3707: 3692: 3676: 3673: 3670: 3661: 3647: 3639: 3623: 3603: 3595: 3591: 3572: 3569: 3566: 3563: 3560: 3554: 3551: 3543: 3525: 3521: 3501: 3485: 3475: 3470: 3463: 3460: 3451: 3447: 3443: 3438: 3431: 3404: 3359: 3356: 3353: 3350: 3347: 3341: 3338: 3316: 3312: 3281: 3263: 3253: 3243: 3238: 3234: 3228: 3225: 3215: 3211: 3205: 3200: 3196: 3189: 3184: 3177: 3174: 3162: 3158: 3144: 3141: 3138: 3135: 3132: 3120: 3110: 3105: 3076: 3066: 3061: 3049: 3044: 3040: 3036: 3031: 3026: 3011: 2995: 2975: 2955: 2952: 2949: 2924: 2909: 2906: 2903: 2898: 2880: 2859: 2855: 2846: 2841: 2837: 2816: 2796: 2776: 2773: 2770: 2748: 2744: 2720: 2717: 2714: 2711: 2708: 2702: 2699: 2691: 2687: 2670: 2667: 2664: 2661: 2658: 2652: 2649: 2627: 2623: 2615: 2593: 2584: 2580: 2563: 2560: 2556: 2547: 2530: 2527: 2523: 2500: 2471: 2439: 2412: 2397: 2381: 2378: 2373: 2369: 2365: 2362: 2359: 2354: 2350: 2327: 2319: 2315: 2309: 2304: 2300: 2296: 2293: 2290: 2285: 2280: 2276: 2271: 2267: 2264: 2261: 2257: 2251: 2247: 2243: 2240: 2237: 2232: 2228: 2223: 2219: 2216: 2213: 2208: 2205: 2202: 2170: 2155: 2137: 2133: 2126: 2119: 2115: 2091: 2087: 2066: 2056: 2053: 2050: 2045: 2032: 2027: 2024: 2021: 2017: 1991: 1981: 1978: 1975: 1970: 1957: 1952: 1949: 1946: 1942: 1933: 1907: 1891: 1888: 1883: 1879: 1875: 1872: 1869: 1864: 1860: 1838: 1832: 1828: 1824: 1821: 1818: 1813: 1809: 1804: 1800: 1797: 1794: 1789: 1786: 1783: 1748: 1730: 1726: 1719: 1716: 1681: 1677: 1612: 1600: 1597: 1582: 1569: 1549: 1534: 1530: 1504: 1463: 1450: 1446: 1442: 1427: 1424: 1419: 1415: 1406: 1388: 1385: 1382: 1378: 1372: 1368: 1364: 1360: 1352: 1348: 1345: 1318: 1314: 1306: 1302: 1255: 1245: 1219: 1211: 1198: 1141: 1138: 1134: 1130: 1129:of the data. 1128: 1124: 1076: 1072: 1034: 1004: 1000: 976: 961: 919: 899: 896: 893: 885: 869: 849: 841: 823: 818: 812: 802: 799: 796: 791: 780: 775: 770: 767: 764: 735: 730: 724: 720: 716: 713: 710: 705: 701: 696: 691: 686: 683: 680: 665: 653: 649: 645: 623: 620: 619: 615: 611: 607: 585: 582: 581: 577: 573: 551: 548: 547: 546: 541:The principle 538: 536: 532: 528: 524: 520: 515: 513: 509: 506: 502: 498: 494: 489: 487: 483: 479: 475: 470: 468: 464: 460: 456: 452: 448: 444: 440: 428: 423: 421: 416: 414: 409: 408: 406: 405: 400: 395: 390: 389: 388: 387: 382: 379: 377: 374: 372: 369: 367: 364: 362: 359: 357: 354: 353: 352: 351: 347: 346: 341: 338: 336: 333: 331: 328: 326: 323: 321: 318: 317: 316: 315: 310: 307: 305: 302: 300: 297: 295: 292: 290: 287: 286: 285: 284: 279: 276: 274: 271: 269: 266: 264: 261: 260: 259: 258: 253: 250: 248: 245: 243: 242:Least squares 240: 239: 238: 237: 233: 232: 227: 224: 223: 222: 221: 216: 213: 211: 208: 206: 203: 201: 198: 196: 193: 191: 188: 186: 183: 181: 178: 176: 175:Nonparametric 173: 171: 168: 167: 166: 165: 160: 157: 155: 152: 150: 147: 145: 144:Fixed effects 142: 140: 137: 136: 135: 134: 129: 126: 124: 121: 119: 118:Ordered logit 116: 114: 111: 109: 106: 104: 101: 99: 96: 94: 91: 89: 86: 84: 81: 79: 76: 74: 71: 69: 66: 65: 64: 63: 58: 55: 53: 50: 48: 45: 43: 40: 39: 38: 37: 33: 32: 29: 26: 25: 21: 20: 9796: 9792:Theil, Henri 9768: 9727: 9721: 9715: 9698: 9692: 9686: 9669: 9663: 9637: 9632: 9607: 9601: 9595: 9444: 9439: 9428:eigenvectors 9424:eigenvectors 9416:eigenvectors 9385: 9331:kernel trick 9328: 9320:transforming 9318:obtained by 9298:. Thus, the 9262:chosen. The 9237: 9187: 9041:, the first 8950: 8948: 8914: 8827: 8770: 8592: 8469: 8181: 8043:compared to 7960: 7858: 7719: 7461: 7328: 7221: 7080: 6892: 6676: 6564: 6415: 6402:column space 6395: 6270: 6197: 5952: 5878: 5681: 5447: 5349: 5218:through the 5080: 4930: 4864: 4718: 4463: 4264: 3927:is given by 3846: 3662: 3636:independent 3512: 3160: 3159: 2689: 2688: 2117: 2116: 1930:, while the 1679: 1678: 1531:, gives the 1444: 1443: 1137:Gauss–Markov 1132: 1131: 1005:Assume that 1002: 1001: 663: 662: 651: 648:PCA loadings 621: 608:regression ( 583: 549: 544: 516: 497:eigenvectors 490: 471: 461:the unknown 446: 442: 436: 299:Non-negative 199: 9386:PCR in the 9339:feature map 9324:feature map 9272:coordinates 9268:feature map 8818:association 8133:linear form 8089:linear form 5955:regularized 5905:eigenvalues 5187:approximate 5112:denote any 4921:linear form 4917:linear form 3012:covariates 3010:transformed 2942:denote the 2809:columns of 2763:denote the 2583:PCA loading 1745:denote the 1047:columns of 975:dimensional 840:data matrix 576:data matrix 501:eigenvalues 482:regularized 309:Regularized 273:Generalized 205:Least angle 103:Mixed logit 9823:Categories 9587:References 9404:kernel PCA 9284:non-linear 9214:non-linear 8811:Mallow's C 7355:, we have 7325:Efficiency 6406:orthogonal 4937:correlated 3542:orthogonal 3540:which has 1445:Objective: 1407:parameter 1142:model for 535:prediction 512:predicting 478:regressors 459:estimating 439:statistics 348:Background 252:Non-linear 234:Estimation 9732:CiteSeerX 9462:× 9364:× 9294:of these 9218:symmetric 9155:… 9143:∈ 9111:… 9099:∈ 9073:× 9020:… 9008:∈ 8755:β 8728:σ 8703:β 8692:β 8673:σ 8654:λ 8602:β 8551:⪰ 8536:^ 8533:β 8523:⁡ 8517:− 8494:^ 8491:β 8481:⁡ 8449:⪰ 8434:^ 8431:β 8421:⁡ 8415:− 8392:^ 8389:β 8379:⁡ 8360:… 8348:∈ 8342:∀ 8318:β 8284:^ 8281:β 8252:≠ 8248:β 8231:− 8205:… 8193:∈ 8150:^ 8147:β 8106:^ 8103:β 8058:^ 8055:β 8030:β 7996:^ 7993:β 7943:⪰ 7928:^ 7925:β 7915:⁡ 7909:− 7886:^ 7883:β 7873:⁡ 7838:⪰ 7823:^ 7820:β 7810:⁡ 7804:− 7781:^ 7778:β 7768:⁡ 7749:… 7737:∈ 7731:∀ 7690:^ 7687:β 7677:⁡ 7656:^ 7653:β 7643:⁡ 7616:β 7582:^ 7579:β 7546:β 7529:− 7489:… 7477:∈ 7424:^ 7421:β 7411:⁡ 7382:^ 7379:β 7369:⁡ 7342:β 7280:^ 7277:β 7249:∗ 7237:^ 7234:β 7180:λ 7173:… 7142:λ 7133:⁡ 7103:− 7093:Λ 7042:− 7032:Λ 7020:− 7001:∗ 6990:− 6947:^ 6944:β 6912:− 6865:∗ 6860:β 6842:− 6815:‖ 6809:∗ 6804:β 6794:− 6786:‖ 6769:∈ 6764:∗ 6759:β 6749:⁡ 6731:^ 6728:β 6692:^ 6689:β 6653:⩽ 6624:− 6615:× 6584:− 6540:∗ 6535:β 6517:− 6490:‖ 6484:∗ 6479:β 6469:− 6461:‖ 6444:∈ 6439:∗ 6434:β 6370:− 6361:× 6334:… 6293:− 6243:∗ 6238:β 6220:− 6162:… 6135:⊥ 6130:∗ 6125:β 6100:∗ 6095:β 6085:− 6057:∈ 6052:∗ 6047:β 6029:problem: 6004:^ 6001:β 5968:⩽ 5830:⩽ 5816:λ 5789:∑ 5736:− 5698:∑ 5400:− 5362:∑ 5329:≤ 5323:≤ 5302:∈ 5282:for some 5161:… 5149:∈ 5123:× 4876:⪰ 4847:⪰ 4832:^ 4829:β 4819:⁡ 4813:− 4790:^ 4787:β 4777:⁡ 4763:we have: 4742:… 4730:∈ 4693:λ 4656:⁡ 4628:∑ 4618:∑ 4602:σ 4583:^ 4580:β 4570:⁡ 4564:− 4541:^ 4538:β 4528:⁡ 4514:we have: 4496:− 4487:… 4475:∈ 4438:λ 4401:⁡ 4379:∑ 4369:∑ 4353:σ 4326:^ 4323:β 4313:⁡ 4292:^ 4289:β 4279:⁡ 4239:λ 4202:⁡ 4180:∑ 4170:∑ 4154:σ 4122:− 4113:λ 4106:… 4095:− 4086:λ 4077:⁡ 4053:σ 4026:− 3973:σ 3954:^ 3951:β 3941:⁡ 3906:^ 3903:β 3870:… 3858:∈ 3730:^ 3727:β 3708:^ 3705:β 3567:… 3555:∈ 3476:∈ 3464:^ 3461:γ 3432:^ 3429:β 3384:β 3354:… 3342:∈ 3254:∈ 3226:− 3178:^ 3175:γ 3142:≤ 3136:≤ 3128:∀ 3111:∈ 3067:∈ 2953:× 2907:… 2774:× 2715:… 2703:∈ 2665:… 2653:∈ 2642:for each 2624:λ 2379:≥ 2370:λ 2366:≥ 2363:⋯ 2360:≥ 2351:λ 2324:Δ 2301:δ 2294:… 2277:δ 2268:⁡ 2248:λ 2241:… 2229:λ 2220:⁡ 2206:× 2199:Λ 2130:Λ 2084:are both 2054:… 2025:× 1979:… 1950:× 1889:≥ 1880:δ 1876:≥ 1873:⋯ 1870:≥ 1861:δ 1829:δ 1822:… 1810:δ 1801:⁡ 1787:× 1780:Δ 1723:Δ 1680:PCA step: 1663:β 1641:β 1598:− 1550:^ 1547:β 1488:β 1464:^ 1461:β 1449:estimator 1416:σ 1386:× 1369:σ 1357:ε 1349:⁡ 1311:ε 1303:⁡ 1279:ε 1246:∈ 1242:β 1216:ε 1208:β 1127:centering 897:≥ 800:… 768:× 714:… 684:× 644:transform 614:dimension 523:collinear 493:variances 215:Segmented 9794:(1971). 9766:(1985). 9550:See also 7605:unbiased 7603:is also 7331:unbiased 6271:where: 6106:‖ 6076:‖ 5767:‖ 5720:‖ 5637:of rank 5426:‖ 5384:‖ 3847:For any 2692:For any 2612:largest 2548:and the 2152:gives a 1405:variance 1071:centered 932:rows of 570:Perform 330:Bayesian 268:Weighted 263:Ordinary 195:Isotonic 190:Quantile 9640:, OUP. 9624:2348005 9406:on the 9302:in the 9264:mapping 9246:into a 8809:or the 6565:where, 1932:columns 1771:where, 503:of the 449:) is a 289:Partial 128:Poisson 9808:  9780:  9734:  9644:  9622:  9426:. The 9280:linear 9244:mapped 9223:. The 9206:linear 8307:biased 7081:where 4931:Under 4865:where 3835:is an 2829:. Let 2736:, let 2190:where 1233:where 884:sample 505:sample 247:Linear 185:Robust 108:Probit 34:Models 9802:46–55 9774:57–60 9620:JSTOR 9394:this 9314:) of 6642:with 2398:) of 2342:with 1852:with 465:in a 294:Total 210:Local 9806:ISBN 9778:ISBN 9642:ISBN 8746:and 8663:< 8588:bias 8309:for 7607:for 7333:for 7130:diag 6677:Let 6659:< 5974:< 5836:< 5220:rank 4074:diag 3163:Let 2581:(or 2486:and 2265:diag 2217:diag 2009:and 1798:diag 1425:> 1337:and 1121:and 862:and 666:Let 642:Now 9742:doi 9728:101 9703:doi 9674:doi 9612:doi 9282:or 9216:), 8919:of 8520:MSE 8478:MSE 8418:Var 8376:Var 8305:is 8135:of 8021:of 7912:MSE 7870:MSE 7807:Var 7765:Var 7674:MSE 7640:Var 7408:MSE 7366:Var 6753:min 6746:arg 6428:min 6041:min 5907:of 4911:is 4816:Var 4774:Var 4567:Var 4525:Var 4310:Var 4276:Var 3938:Var 2156:of 2092:of 1934:of 1908:of 1749:of 1632:of 1527:is 1346:Var 1164:on 1125:to 572:PCA 488:. 447:PCR 437:In 9825:: 9804:. 9776:. 9740:. 9726:. 9699:35 9697:. 9670:23 9668:. 9652:^ 9618:. 9608:31 9606:. 9442:. 9383:. 9326:. 9254:) 9235:. 9180:. 8590:. 8179:. 6674:. 5679:. 5347:. 3839:. 3500:. 3157:. 2686:. 2598:th 1676:. 1535:: 622:3. 584:2. 550:1. 469:. 441:, 9814:. 9786:. 9748:. 9744:: 9709:. 9705:: 9680:. 9676:: 9626:. 9614:: 9531:T 9526:X 9520:X 9497:T 9492:X 9486:X 9465:n 9459:n 9367:n 9361:n 9164:} 9161:m 9158:, 9152:, 9149:1 9146:{ 9140:k 9120:} 9117:p 9114:, 9108:, 9105:1 9102:{ 9096:m 9076:m 9070:n 9049:m 9029:} 9026:p 9023:, 9017:, 9014:1 9011:{ 9005:m 8985:p 8962:p 8928:X 8887:X 8881:T 8876:X 8853:X 8847:T 8842:X 8813:p 8792:X 8786:T 8781:X 8732:2 8707:. 8697:T 8686:/ 8682:) 8677:2 8669:p 8666:( 8658:j 8631:h 8628:t 8624:j 8574:k 8554:0 8548:) 8543:k 8526:( 8514:) 8508:s 8505:l 8502:o 8484:( 8455:, 8452:0 8446:) 8441:k 8424:( 8412:) 8406:s 8403:l 8400:o 8382:( 8372:: 8369:} 8366:p 8363:, 8357:, 8354:1 8351:{ 8345:k 8291:k 8256:0 8242:T 8237:) 8234:k 8228:p 8225:( 8221:V 8217:, 8214:} 8211:p 8208:, 8202:, 8199:1 8196:{ 8190:k 8164:s 8161:l 8158:o 8113:k 8072:s 8069:l 8066:o 8003:k 7969:k 7946:0 7940:) 7935:k 7918:( 7906:) 7900:s 7897:l 7894:o 7876:( 7844:, 7841:0 7835:) 7830:j 7813:( 7801:) 7795:s 7792:l 7789:o 7771:( 7761:: 7758:} 7755:p 7752:, 7746:, 7743:1 7740:{ 7734:j 7705:. 7702:) 7697:k 7680:( 7671:= 7668:) 7663:k 7646:( 7589:k 7554:0 7550:= 7540:T 7535:) 7532:k 7526:p 7523:( 7519:V 7498:} 7495:p 7492:, 7486:, 7483:1 7480:{ 7474:k 7447:, 7444:) 7438:s 7435:l 7432:o 7414:( 7405:= 7402:) 7396:s 7393:l 7390:o 7372:( 7309:k 7287:k 7245:L 7207:. 7203:) 7197:2 7193:/ 7189:1 7184:p 7176:, 7170:, 7165:2 7161:/ 7157:1 7152:1 7149:+ 7146:k 7137:( 7127:= 7122:2 7118:/ 7114:1 7109:) 7106:k 7100:p 7097:( 7066:, 7061:2 7057:/ 7053:1 7048:) 7045:k 7039:p 7036:( 7026:) 7023:k 7017:p 7014:( 7010:V 7006:= 6996:) 6993:k 6987:p 6984:( 6980:L 6954:L 6918:) 6915:k 6909:p 6906:( 6902:L 6878:. 6874:0 6870:= 6853:T 6848:) 6845:k 6839:p 6836:( 6832:L 6819:2 6798:X 6790:Y 6779:p 6774:R 6743:= 6738:L 6699:L 6662:p 6656:k 6650:1 6630:) 6627:k 6621:p 6618:( 6612:p 6590:) 6587:k 6581:p 6578:( 6574:L 6549:0 6545:= 6528:T 6523:) 6520:k 6514:p 6511:( 6507:L 6494:2 6473:X 6465:Y 6454:p 6449:R 6381:. 6376:) 6373:k 6367:p 6364:( 6358:p 6353:] 6347:p 6342:v 6337:, 6331:, 6326:1 6323:+ 6320:k 6315:v 6309:[ 6304:= 6299:) 6296:k 6290:p 6287:( 6283:V 6256:, 6252:0 6248:= 6231:T 6226:) 6223:k 6217:p 6214:( 6210:V 6183:. 6180:} 6175:p 6170:v 6165:, 6159:, 6154:1 6151:+ 6148:k 6143:v 6138:{ 6111:2 6089:X 6081:Y 6067:p 6062:R 6011:k 5977:p 5971:k 5965:1 5928:X 5922:T 5917:X 5891:k 5857:p 5854:= 5851:k 5846:0 5839:p 5833:k 5827:1 5820:j 5810:n 5805:1 5802:+ 5799:k 5796:= 5793:j 5782:{ 5777:= 5772:2 5761:k 5756:i 5751:x 5744:k 5740:V 5731:i 5726:x 5713:n 5708:1 5705:= 5702:i 5666:X 5645:k 5621:k 5601:k 5581:, 5576:i 5571:x 5564:T 5559:k 5555:V 5551:= 5546:k 5541:i 5536:x 5531:= 5526:i 5521:z 5499:k 5479:, 5474:k 5470:V 5466:= 5461:k 5457:L 5431:2 5420:i 5415:z 5408:k 5404:L 5395:i 5390:x 5377:n 5372:1 5369:= 5366:i 5335:) 5332:n 5326:i 5320:1 5317:( 5312:k 5307:R 5297:i 5292:z 5268:i 5263:z 5256:k 5252:L 5229:k 5204:i 5199:x 5173:. 5170:} 5167:p 5164:, 5158:, 5155:1 5152:{ 5146:k 5126:k 5120:p 5098:k 5094:L 5061:0 5033:0 5012:X 5006:T 5001:X 4974:X 4948:X 4899:A 4879:0 4873:A 4850:0 4844:) 4839:k 4822:( 4810:) 4804:s 4801:l 4798:o 4780:( 4751:} 4748:p 4745:, 4739:, 4736:1 4733:{ 4727:k 4704:. 4697:j 4686:T 4681:j 4676:v 4669:j 4664:v 4651:p 4646:1 4643:+ 4640:k 4637:= 4634:j 4606:2 4598:= 4595:) 4590:k 4573:( 4561:) 4555:s 4552:l 4549:o 4531:( 4502:} 4499:1 4493:p 4490:, 4484:, 4481:1 4478:{ 4472:k 4449:. 4442:j 4431:T 4426:j 4421:v 4414:j 4409:v 4396:p 4391:1 4388:= 4385:j 4357:2 4349:= 4346:) 4340:s 4337:l 4334:o 4316:( 4307:= 4304:) 4299:p 4282:( 4250:. 4243:j 4232:T 4227:j 4222:v 4215:j 4210:v 4197:k 4192:1 4189:= 4186:j 4158:2 4150:= 4145:T 4140:k 4136:V 4131:) 4125:1 4117:k 4109:, 4103:, 4098:1 4090:1 4081:( 4068:k 4064:V 4057:2 4049:= 4044:T 4039:k 4035:V 4029:1 4022:) 4016:k 4012:W 4006:T 4001:k 3997:W 3993:( 3988:k 3984:V 3977:2 3969:= 3966:) 3961:k 3944:( 3913:k 3879:} 3876:p 3873:, 3867:, 3864:1 3861:{ 3855:k 3823:V 3803:V 3799:X 3795:= 3790:p 3786:V 3781:X 3777:= 3772:p 3768:W 3744:s 3741:l 3738:o 3720:= 3715:p 3677:p 3674:= 3671:k 3648:k 3624:k 3604:k 3576:} 3573:p 3570:, 3564:, 3561:1 3558:{ 3552:k 3526:k 3522:W 3486:p 3481:R 3471:k 3452:k 3448:V 3444:= 3439:k 3405:k 3363:} 3360:p 3357:, 3351:, 3348:1 3345:{ 3339:k 3317:k 3313:W 3291:Y 3264:k 3259:R 3250:Y 3244:T 3239:k 3235:W 3229:1 3222:) 3216:k 3212:W 3206:T 3201:k 3197:W 3193:( 3190:= 3185:k 3145:n 3139:i 3133:1 3121:p 3116:R 3106:i 3101:x 3077:k 3072:R 3062:i 3057:x 3050:T 3045:k 3041:V 3037:= 3032:k 3027:i 3022:x 2996:W 2976:k 2956:k 2950:n 2930:] 2925:k 2920:v 2914:X 2910:, 2904:, 2899:1 2894:v 2888:X 2884:[ 2881:= 2860:k 2856:V 2851:X 2847:= 2842:k 2838:W 2817:V 2797:k 2777:k 2771:p 2749:k 2745:V 2724:} 2721:p 2718:, 2712:, 2709:1 2706:{ 2700:k 2674:} 2671:p 2668:, 2662:, 2659:1 2656:{ 2650:j 2628:j 2594:j 2564:h 2561:t 2557:j 2531:h 2528:t 2524:j 2501:j 2496:v 2472:j 2467:v 2461:X 2440:V 2419:X 2413:T 2408:X 2382:0 2374:p 2355:1 2328:2 2320:= 2316:] 2310:2 2305:p 2297:, 2291:, 2286:2 2281:1 2272:[ 2262:= 2258:] 2252:p 2244:, 2238:, 2233:1 2224:[ 2214:= 2209:p 2203:p 2177:X 2171:T 2166:X 2138:T 2134:V 2127:V 2101:X 2072:] 2067:p 2062:v 2057:, 2051:, 2046:1 2041:v 2036:[ 2033:= 2028:p 2022:p 2018:V 1997:] 1992:p 1987:u 1982:, 1976:, 1971:1 1966:u 1961:[ 1958:= 1953:p 1947:n 1943:U 1917:X 1892:0 1884:p 1865:1 1839:] 1833:p 1825:, 1819:, 1814:1 1805:[ 1795:= 1790:p 1784:p 1758:X 1731:T 1727:V 1720:U 1717:= 1713:X 1691:X 1619:Y 1613:T 1608:X 1601:1 1594:) 1589:X 1583:T 1578:X 1573:( 1570:= 1564:s 1561:l 1558:o 1514:X 1428:0 1420:2 1389:n 1383:n 1379:I 1373:2 1365:= 1361:) 1353:( 1323:0 1319:= 1315:) 1307:( 1300:E 1256:p 1251:R 1220:, 1212:+ 1203:X 1199:= 1195:Y 1173:X 1151:Y 1108:X 1086:X 1056:X 1035:p 1014:Y 986:Y 962:p 941:X 920:n 900:p 894:n 870:p 850:n 824:T 819:) 813:n 808:x 803:, 797:, 792:1 787:x 781:( 776:= 771:p 765:n 760:X 736:T 731:) 725:n 721:y 717:, 711:, 706:1 702:y 697:( 692:= 687:1 681:n 676:Y 445:( 426:e 419:t 412:v

Index

Regression analysis
Linear regression
Simple regression
Polynomial regression
General linear model
Generalized linear model
Vector generalized linear model
Discrete choice
Binomial regression
Binary regression
Logistic regression
Multinomial logistic regression
Mixed logit
Probit
Multinomial probit
Ordered logit
Ordered probit
Poisson
Multilevel model
Fixed effects
Random effects
Linear mixed-effects model
Nonlinear mixed-effects model
Nonlinear regression
Nonparametric
Semiparametric
Robust
Quantile
Isotonic
Principal components

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