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--- seminars:stat:201001 [2020/09/17 18:30] – created qyu
+++ seminars:stat:201001 [2020/09/17 18:32] (current) – qyu
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+<WRAP centeralign>##Statistics Seminar##\\ Department of Mathematical Sciences</WRAP>
+<WRAP 70% center>
+^  **DATE:**|Thursday, Oct. 1, 2020 |
+^  **TIME:**|1:15pm -- 2:15pm |
+^  **LOCATION:**|Zoom Meeting |
+^  **SPEAKER:**|Yishi Wang, University of North Carolina Wilmington University |
+^  **TITLE:**|Inference of a two-sample order free trend test  |
+</WRAP>
+\\
+<WRAP center box 80%>
+<WRAP centeralign>**Abstract**</WRAP>
+A new nonparametric methodology is developed for testing whether two independent
+groups sharing the same changing pattern from a response variable, over multiple
+ordered sub-populations in each of the two groups. The question is formalized into a
+nonparametric two-sample comparison problem for the stochastic order among
+subsamples, through U-statistics with accommodations for zero-inflated
+distributions. A novel bootstrap procedure is proposed to obtain the critical values
+with given type I error. Following the procedure, bootstrapped p-values are obtained
+through simulated samples. It is proven that the distribution of the test statistics
+is independent from the underlying distributions of the subsamples, when certain
+sufficient statistics provided. Furthermore, this study also develops a feasible
+framework for power studies to determine sample sizes, which is necessary in
+real-world applications. Simulation results suggest that the test is consistent. The
+methodology is illustrated using a biological experiment with a split-plot design,
+and significant differences in changing patterns of seed weight between treatments
+are found with relative small subsample sizes. The asymptotic distribution of the
+test is also investigated.
+</WRAP>