A Mann-Whitney test indicates whether a numeric column’s values appear to be larger in one of two categories. If the values are drawn from distributions having the same shape but different locations across categories, the Mann-Whitney test can be interpreted as a test of whether the group medians are equal.

To perform a Mann-Whitney test:

- In the Summary view, use the confidence slider to choose a desired confidence level
- Choose the numeric column of interest on the left
- Choose a category column that takes two values in the Covariate table
- Click the button labeled
*Boxes*below the Covariate view - The result of the Mann-Whitney test will appear in the Bottom Line

Note that even if the observed medians are equal across categories, the Mann-Whitney test can indicate that the population medians are not equal. This is most likely due to the distribution of values differing across categories.

To analyze differences in a numeric column’s median across three or more categories, use a Kruskal-Wallis test.

See also:

- Performing a Mann-Whitney test of two numeric columns’ medians
- Performing a Kruskal-Wallis test of a numeric column’s median across values of another columns
- Performing a t-test of a numeric column’s mean across two categories
- Performing a Kolmogorov-Smirnov test of a numeric column’s distribution across values of another column
- Viewing the correlation coefficient between two numeric columns
- Formatting descriptive and inferential statistics
- About the Summary view