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Mann-Whitney Test


The Wilcoxon Mann Whitney test is a common nonparametric test when comparing two samples with non-normal distributions. It is a powerful substitution of two-sample t-test.

It is used to test whether the two samples have identical distribution or not.

This test is also valid when the observations in a sample of data are ranks, that is, ordinary data.

To perform a Mann-Whitney test:

  1. Select Statistics: Nonparametric Tests: Mann-Whitney Test. This opens the mwtest dialog box.
  2. Specify the Data Range and the desired Alternate Hypothesis. Then check Exact P Value box for exact p-value.
  3. Upon clicking OK, an analysis report sheet is generated that lists the ranks table, degrees of freedom, the U and Z statistic, the associated p-value, and the test conclusion.
Note: Origin provides both asymptotic and exact p-value as result for Mann-Whitney test.

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