| Dewei Wang, Department of Statistics, University of South Carolina, Hosted by Yang Li |
| Title: Nonparametric goodness-of-fit tests for uniform stochastic ordering |
| Abstract:In this talk, I will introduce a new nonparametric procedure for testing against uniform stochastic ordering in a two-population setting. Uniform stochastic ordering is stronger than ordinary stochastic ordering but weaker than likelihood ratio ordering. Uniform stochastic ordering is satisfied when the ordinal dominance curve associated with the two distributions is star-shaped. To develop a goodness-of-fit test for this property, we construct test statistics by examining the discrepancy between the empirical ordinal dominance curve and its the least star-shaped majorant. We derive the limiting distribution of these statistics when uniform stochastic ordering is satisfied or not, and further we establish the least favorable distribution that can be used to determine the critical values. We illustrate the performance of our testing procedure through simulation and by applying it to a caffeine study involving premature infants conducted by Palmetto Health Richland in Columbia, SC. |