Title: Tolerance bands for exponential family functional data

Abstract: A tolerance band for a functional response provides a region that is expected to contain a given fraction of observations from the sampled population at each point in the domain. This band is a functional analogue of the tolerance interval for a univariate response. Although the problem of constructing functional tolerance bands has been considered for a Gaussian response, it has not been investigated for non-Gaussian responses, which are common in biomedical applications. We describe a methodology for constructing tolerance bands for two non-Gaussian members of the exponential family: binomial and Poisson. The approach is to first model the data using the framework of generalized functional principal components analysis. Then, a parameter is identified in which the marginal distribution of the response is stochastically monotone. We show that the tolerance limits can be readily obtained from confidence limits for this parameter, which in turn can be computed using large-sample theory and bootstrapping. The proposed methodology works for both dense and sparse functional data. We report the results of simulation studies designed to evaluate its performance and get recommendations for practical applications. The methodology is illustrated using two actual biomedical studies.

Brief Bio: Dr. Pankaj Choudhary is a professor of statistics in the Department of Mathematical Sciences at the University of Texas (UT) at Dallas. He received his bachelor’s and master’s degrees in statistics in India and his PhD in statistics from the Ohio State University in 2002. He has been at UT Dallas since then. His current research interests include development of risk prediction models for contralateral breast cancer and substance use disorders, modeling and analysis of method comparison studies, and construction of tolerance regions. In his free time, he likes to watch TV with his family.