Kruskal-Wallis H Test

Use: The Kruskal-Wallis test is a non-parametric method used to determine if there are statistically significant differences between three or more independent groups. It's suitable for non-normally distributed data or ordinal data.

Example: Assessing whether there is a difference in pain relief among three different painkillers in a clinical trial.

Column Requirement: Continuous data for the response variable and a categorical variable for groups.

Steps:

1. Select a continuous variable (e.g., scores) and a categorical variable (e.g., treatments).

2. Check for assumptions such as independence and ordinal data.

3. Perform the Kruskal-Wallis test to compare medians.

4. Evaluate the p-value. A low p-value indicates significant differences between groups.

5. Conduct post-hoc tests for pairwise comparisons if the Kruskal-Wallis test is significant.