Wilcoxon Signed Ranks Test

Several statistical tests exist for comparing data groups depending on the group number, sample size, data collection method, and population distribution. The Wilcoxon signed ranks test is the nonparametric equivalent of the matched-pairs difference t test for two dependent samples. The test examines whether or not the differences between the ranks of paired data come from a population with a median equal to zero. This entry reviews the assumptions and requirements for this text, explains the test statistic, and illustrates its application in education with an example.