The Wilcoxon rank sum test is a nonparametric statistical test used to compare two independent groups to determine if they come from the same distribution. It does not assume that the data are normally distributed, making it a useful alternative to the independent samples t-test when normality cannot be assumed.
For example, researchers might use the Wilcoxon rank sum test to compare the test scores of students who studied using two different methods if the scores are skewed or ordinal rather than normally distributed.
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