Optimal sub-Gaussian variance proxy for truncated Gaussian and exponential random variables

Fuente: arXiv
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Hauptverfasser: Barreto, Mathias, Marchal, Olivier, Arbel, Julyan
Format: Preprint
Veröffentlicht: 2024
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author Barreto, Mathias
Marchal, Olivier
Arbel, Julyan
author_facet Barreto, Mathias
Marchal, Olivier
Arbel, Julyan
contents This paper establishes the optimal sub-Gaussian variance proxy for truncated Gaussian and truncated exponential random variables. The proofs rely on first characterizing the optimal variance proxy as the unique solution to a set of two equations and then observing that for these two truncated distributions, one may find explicit solutions to this set of equations. Moreover, we establish the conditions under which the optimal variance proxy coincides with the variance, thereby characterizing the strict sub-Gaussianity of the truncated random variables. Specifically, we demonstrate that truncated Gaussian variables exhibit strict sub-Gaussian behavior if and only if they are symmetric, meaning their truncation is symmetric with respect to the mean. Conversely, truncated exponential variables are shown to never exhibit strict sub-Gaussian properties. These findings contribute to the understanding of these prevalent probability distributions in statistics and machine learning, providing a valuable foundation for improved and optimal modeling and decision-making processes.
format Preprint
id arxiv_https___arxiv_org_abs_2403_08628
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimal sub-Gaussian variance proxy for truncated Gaussian and exponential random variables
Barreto, Mathias
Marchal, Olivier
Arbel, Julyan
Statistics Theory
Methodology
60E05, 00A05
This paper establishes the optimal sub-Gaussian variance proxy for truncated Gaussian and truncated exponential random variables. The proofs rely on first characterizing the optimal variance proxy as the unique solution to a set of two equations and then observing that for these two truncated distributions, one may find explicit solutions to this set of equations. Moreover, we establish the conditions under which the optimal variance proxy coincides with the variance, thereby characterizing the strict sub-Gaussianity of the truncated random variables. Specifically, we demonstrate that truncated Gaussian variables exhibit strict sub-Gaussian behavior if and only if they are symmetric, meaning their truncation is symmetric with respect to the mean. Conversely, truncated exponential variables are shown to never exhibit strict sub-Gaussian properties. These findings contribute to the understanding of these prevalent probability distributions in statistics and machine learning, providing a valuable foundation for improved and optimal modeling and decision-making processes.
title Optimal sub-Gaussian variance proxy for truncated Gaussian and exponential random variables
topic Statistics Theory
Methodology
60E05, 00A05
url https://arxiv.org/abs/2403.08628