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Main Authors: Derumigny, Alexis, Schmidt-Hieber, Johannes
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2303.11706
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author Derumigny, Alexis
Schmidt-Hieber, Johannes
author_facet Derumigny, Alexis
Schmidt-Hieber, Johannes
contents In nonparametric statistics, rate-optimal estimators typically balance bias and stochastic error. The recent work on overparametrization raises the question whether rate-optimal estimators exist that do not obey this trade-off. In this work we consider pointwise estimation in the Gaussian white noise model with regression function $f$ in a class of $β$-Hölder smooth functions. Let 'worst-case' refer to the supremum over all functions $f$ in the Hölder class. It is shown that any estimator with worst-case bias $\lesssim n^{-β/(2β+1)}=: ψ_n$ must necessarily also have a worst-case mean absolute deviation that is lower bounded by $\gtrsim ψ_n.$ To derive the result, we establish abstract inequalities relating the change of expectation for two probability measures to the mean absolute deviation.
format Preprint
id arxiv_https___arxiv_org_abs_2303_11706
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Lower bounds for the trade-off between bias and mean absolute deviation
Derumigny, Alexis
Schmidt-Hieber, Johannes
Statistics Theory
62C20, 62G05, 62C05
In nonparametric statistics, rate-optimal estimators typically balance bias and stochastic error. The recent work on overparametrization raises the question whether rate-optimal estimators exist that do not obey this trade-off. In this work we consider pointwise estimation in the Gaussian white noise model with regression function $f$ in a class of $β$-Hölder smooth functions. Let 'worst-case' refer to the supremum over all functions $f$ in the Hölder class. It is shown that any estimator with worst-case bias $\lesssim n^{-β/(2β+1)}=: ψ_n$ must necessarily also have a worst-case mean absolute deviation that is lower bounded by $\gtrsim ψ_n.$ To derive the result, we establish abstract inequalities relating the change of expectation for two probability measures to the mean absolute deviation.
title Lower bounds for the trade-off between bias and mean absolute deviation
topic Statistics Theory
62C20, 62G05, 62C05
url https://arxiv.org/abs/2303.11706