Seminar: High-dimensional Covariance Structure Testing using Maximum Pairwise Bayes Factors
27/06/2019

Professor Lizhen Lin, Department of Applied and Computational Mathematics and Statistics, University of Notre Dame.

  • Time: 10:00, 8 July 2019

Abstract: High-dimensional Covariance Structure Testing using Maximum Pairwise Bayes Factors 

Hypothesis testing of structure in covariance matrices is of significant importance, but faces great challenges in high-dimensional settings. Although consistent frequentist one-sample covariance tests have been proposed, there is a lack of simple, computationally scalable, and theoretically sound Bayesian testing methods for large covariance matrices. Motivated by this gap and by the need for tests that are powerful against sparse alternatives, we propose a novel testing framework based on the maximum pairwise Bayes factor. Our initial focus is on one-sample covariance testing; the proposed test can optimally distinguish null and alternative hypotheses in a frequentist asymptotic sense. We then propose diagonal tests and a scalable covariance graph selection procedure that are shown to be consistent. Further, our procedure can effectively control false positives. A simulation study evaluates the proposed approach relative to competitors. The performance of our graph selection method is demonstrated through applications to several real data sets.

 
 
Khoa Toán - Tin học, Trường Đại học Khoa học Tự nhiên, Đại học Quốc gia TP Hồ Chí Minh.
Phòng F.009, cơ sở 227 Nguyễn Văn Cừ, Quận 5, TP HCM.