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arXiv 2310.00532math.STcs.LGstat.TH
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自适应线性模型的统计极限:低维估计与推断

Statistical Limits of Adaptive Linear Models: Low-Dimensional Estimation and Inference

University of California, Berkeley(加州大学伯克利分校);Rutgers University - New Brunswick(罗格斯大学新布朗斯维克分校)

Licong Lin, Mufang Ying, Suvrojit Ghosh, Koulik Khamaru, Cun-Hui Zhang

AI总结:

本文研究自适应数据收集对高维线性模型中低维参数估计与推断的影响,刻画了估计误差与自适应程度的关系,并提出基于两阶段自适应线性估计方程(TALE)的单坐标推断估计量并证明其渐近正态性。

摘要:

当数据以自适应方式收集时,统计学中的估计与推断面临重大挑战。即使在线性模型中,普通最小二乘(OLS)估计量在单坐标估计中也可能无法表现出渐近正态性,并且误差会被放大。这一问题由最近的一个极小化极大下界所凸显:与独立同分布(i.i.d.)数据的情形相比,当数据被允许任意自适应地收集时,估计单个坐标的误差可能被放大 $\sqrt{d}$ 倍。我们的工作探讨了使用 i.i.d. 数据与自适应数据之间在估计性能上的这一显著差异。我们研究了数据收集中的自适应程度如何影响高维线性模型中低维参数分量的估计性能。我们识别出数据收集机制上的一些条件,在这些条件下,低维参数分量的估计误差与 i.i.d. 情形下的对应误差相匹配,至多相差一个依赖于自适应程度的因子。我们证明 OLS 或对中心化数据使用 OLS 可以达到这一匹配误差。此外,我们通过求解一个两阶段自适应线性估计方程(TALE),提出了一种用于单坐标推断的新型估计量。在数据收集满足较弱自适应形式的条件下,我们建立了所提估计量的渐近正态性。

英文摘要:

Estimation and inference in statistics pose significant challenges when data are collected adaptively. Even in linear models, the Ordinary Least Squares (OLS) estimator may fail to exhibit asymptotic normality for single coordinate estimation and have inflated error. This issue is highlighted by a recent minimax lower bound, which shows that the error of estimating a single coordinate can be enlarged by a multiple of $\sqrt{d}$ when data are allowed to be arbitrarily adaptive, compared with the case when they are i.i.d. Our work explores this striking difference in estimation performance between utilizing i.i.d. and adaptive data. We investigate how the degree of adaptivity in data collection impacts the performance of estimating a low-dimensional parameter component in high-dimensional linear models. We identify conditions on the data collection mechanism under which the estimation error for a low-dimensional parameter component matches its counterpart in the i.i.d. setting, up to a factor that depends on the degree of adaptivity. We show that OLS or OLS on centered data can achieve this matching error. In addition, we propose a novel estimator for single coordinate inference via solving a Two-stage Adaptive Linear Estimating equation (TALE). Under a weaker form of adaptivity in data collection, we establish an asymptotic normality property of the proposed estimator.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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