How to: Friedman test

Friedman's test is a nonparametric test to compare three or more matched groups.

1. Enter data

From the Welcome (or New Table and graph) dialog, choose the Column tab and a before-after graph.

If you aren't ready to enter your own data, choose to use sample data, and choose: One-way ANOVA - Repeated-measures.

Enter the data for each group into a separate column. Enter data for each subject (or each matched set of results) on a separate row. Optionally, identify the subjects with row titles. If you leave any values blank, Prism will not be able to perform Friedman's test.

2. Choose Friedman's test

1.	From the data table, click on the toolbar.

2.	Choose one-way ANOVA from the list of column analyses.

3.	On the ANOVA dialog, choose Friedman's test.

3. Choose a post test

Prism only offers Dunn's post test, either to compare all pairs of groups, or just selected pairs.

4. Review the results and view the graph

ANOVA investigates the likelihood that the difference among the means could have been caused by chance. The most important results are the P value and the results of post tests.

Before accepting the results, review the analysis checklist.