Overview for Mann-Whitney Test

Use Mann-Whitney Test to do the following:
  • Determine whether the population medians of two groups differ.
  • Calculate a range of values that is likely to include the difference between the population medians.

For example, a consultant compares the payrolls of two companies to determine whether their median salaries differ. If the medians from the two companies are different, the consultant uses the confidence interval to determine whether the difference is practically significant.

Where to find this analysis

To perform a Mann-Whitney, choose Stat > Nonparametrics > Mann-Whitney.

When to use an alternate analysis

If you have more than 15 observations in each sample, or if your data aren't severely skewed, use 2-Sample t because the test has more power.