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Linear Regression with Heteroskedastic Errors
Proceedings of the 42nd Conference on Uncertainty in Artificial Intelligence, PMLR 337:1054-1080, 2026.
Abstract
We study the classic linear regression problem under the challenging setting of heteroskedastic noise. We study a model in which we have $n$ sources that each observe linear measurements of an unknown $d$-dimensional vector $\beta$. Each source has an unknown and distinct variance for the error, and the goal is to estimate the parameter vector $\beta$, under the assumption that there exist \emph{sufficiently many} sources with small error (specifically, $m$ sources have variance at most $1$). Our results show that $\beta$ can be estimated to sub-constant error, as long as the number of small-error sources, i.e., $m$, is large enough. We prove two main results. First, we show that even with just one observation per source, under minimal assumptions on the linear measurements, $\beta$ can be estimated to sub-constant error when $m \ge n^{1- \frac{1}{4d}}$. Second, we show that if we have access to \emph{two} observations per source, under similar assumptions on the linear measurements, $\beta$ can be estimated to sub-constant error when $m \ge n^{5/6}$. Our results are related to the recent line of work on mean estimation with heteroskedastic variances, and more specifically, the \emph{subset of signals} model used in this literature. To the best of our knowledge, our results provide the first sub-constant recovery guarantees for regression in this model.