Science and Education Publishing American Journal of Applied Mathematics and Statistics 2328-7292 1 1 2013 10 22 Robustness and Power of the Kornbrot Rank Difference, Signed Ranks, and Dependent Samples T-test 99 102 EN Norman N. Haidous Department of Evaluation and Research, Wayne State University, Detroit, USA Shlomo S. Sawilowsky AJAMS2013154 10.12691/ajams-1-5-4 2013 09 27 2013 10 15 2013 10 22 The purpose of the study was to compare the power and accuracy of the Kornbrot rank difference test to classical parametric and nonparametric alternatives when the assumption of normality is not met, the data are ordinal, and the sample size is small. Although the procedure is robust, there was no evidence the rank difference test had power advantages over Wilcoxon Signed-Ranks test.