Edgeworth approximations for spiked PCA models and applications

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Abstract/Contents

Abstract
We study improved approximations to the distributions of the largest eigenvalues of the sample covariance matrix of i.i.d. zero-mean Gaussian random vectors, in the high-dimensional regime where the ratio of the dimension of each observation to the number of observations converges to a positive constant. Assuming that a fixed number of population principal components have "supercritical" variances and that the remaining noise components have common variance 1, we derive Edgeworth corrections to the limiting Gaussian distributions of the supercritical sample eigenvalues. The Edgeworth correction involves a quadratic polynomial, as in classical settings, but the coefficients reflect the high-dimensional structure and exhibit the repulsion between supercritical eigenvalues. The methods involve Edgeworth expansions for sums of independent non-identically distributed variates obtained by conditioning on the other sample eigenvalues, and the limiting bulk properties and fluctuations of these eigenvalues. As an application, we consider post-selective inference for supercritical eigenvalues. Empirical study shows that Edgeworth approximations can improve the inference, along with a better asymptotic accuracy guarantee than the normal approximation.

Description

Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2019; ©2019
Publication date 2019; 2019
Issuance monographic
Language English

Creators/Contributors

Author Yang, Jeha
Degree supervisor Johnstone, Iain
Thesis advisor Johnstone, Iain
Thesis advisor Donoho, David Leigh
Thesis advisor Owen, Art B
Degree committee member Donoho, David Leigh
Degree committee member Owen, Art B
Associated with Stanford University, Department of Statistics.

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Jeha Yang.
Note Submitted to the Department of Statistics.
Thesis Thesis Ph.D. Stanford University 2019.
Location electronic resource

Access conditions

Copyright
© 2019 by Jeha Yang
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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