Friedman Test

Use: The Friedman test is a non-parametric alternative to ANOVA, used for repeated measures or within-subject designs. It determines if there are differences among the groups across multiple treatments or conditions.

Example: Testing if there are significant differences in the preferences of individuals for three different types of mobile phones before and after a marketing campaign.

Column Requirement: Paired or matched continuous data across multiple groups.

Steps:

1. Select columns with continuous data representing matched groups (e.g., performance of individuals on three different occasions).

2. Ensure that the data is paired or matched.

3. Perform the Friedman test.

4. Evaluate the test statistic and associated p-value.

5. A low p-value suggests significant differences among the matched groups.