Kruskal-Wallis
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Stat > Nonparametrics > Kruskal-Wallis

You can perform a Kruskal-Wallis test of the equality of medians for two or more populations.

This test is a generalization of the procedure used by the Mann-Whitney test and, like Mood's Median test, offers a nonparametric alternative to the one-way analysis of variance. The Kruskal-Wallis hypotheses are:

H0: the population medians are all equal versus H1: the medians are not all equal

An assumption for this test is that the samples from the different populations are independent random samples from continuous distributions, with the distributions having the same shape. The Kruskal-Wallis test is more powerful than Mood's median test for data from many distributions, including data from the normal distribution, but is less robust against outliers.

Dialog box items

Response: Enter the column that contains the response variable from all the samples.

Factor: Enter the column that contains the factor levels.