Finite Sample Analysis of Distribution-Free Confidence Ellipsoids for Linear Regression

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Autori principali: Szentpéteri, Szabolcs, Csáji, Balázs Csanád
Natura: Preprint
Pubblicazione: 2024
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author Szentpéteri, Szabolcs
Csáji, Balázs Csanád
author_facet Szentpéteri, Szabolcs
Csáji, Balázs Csanád
contents The least squares (LS) estimate is the archetypical solution of linear regression problems. The asymptotic Gaussianity of the scaled LS error is often used to construct approximate confidence ellipsoids around the LS estimate, however, for finite samples these ellipsoids do not come with strict guarantees, unless some strong assumptions are made on the noise distributions. The paper studies the distribution-free Sign-Perturbed Sums (SPS) ellipsoidal outer approximation (EOA) algorithm which can construct non-asymptotically guaranteed confidence ellipsoids under mild assumptions, such as independent and symmetric noise terms. These ellipsoids have the same center and orientation as the classical asymptotic ellipsoids, only their radii are different, which radii can be computed by convex optimization. Here, we establish high probability non-asymptotic upper bounds for the sizes of SPS outer ellipsoids for linear regression problems and show that the volumes of these ellipsoids decrease at the optimal rate. Finally, the difference between our theoretical bounds and the empirical sizes of the regions are investigated experimentally.
format Preprint
id arxiv_https___arxiv_org_abs_2409_08801
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Finite Sample Analysis of Distribution-Free Confidence Ellipsoids for Linear Regression
Szentpéteri, Szabolcs
Csáji, Balázs Csanád
Signal Processing
Statistics Theory
Machine Learning
The least squares (LS) estimate is the archetypical solution of linear regression problems. The asymptotic Gaussianity of the scaled LS error is often used to construct approximate confidence ellipsoids around the LS estimate, however, for finite samples these ellipsoids do not come with strict guarantees, unless some strong assumptions are made on the noise distributions. The paper studies the distribution-free Sign-Perturbed Sums (SPS) ellipsoidal outer approximation (EOA) algorithm which can construct non-asymptotically guaranteed confidence ellipsoids under mild assumptions, such as independent and symmetric noise terms. These ellipsoids have the same center and orientation as the classical asymptotic ellipsoids, only their radii are different, which radii can be computed by convex optimization. Here, we establish high probability non-asymptotic upper bounds for the sizes of SPS outer ellipsoids for linear regression problems and show that the volumes of these ellipsoids decrease at the optimal rate. Finally, the difference between our theoretical bounds and the empirical sizes of the regions are investigated experimentally.
title Finite Sample Analysis of Distribution-Free Confidence Ellipsoids for Linear Regression
topic Signal Processing
Statistics Theory
Machine Learning
url https://arxiv.org/abs/2409.08801