The null hypothesis for Friedman's ANOVA states what?

The null hypothesis for Friedman's ANOVA states what?

• A. All possible rankings of observations are equally as likely
• B. Means are equal across groups
• C. Variances are equal
• D. Proportions are equal

Answer: (A)

Friedman’s ANOVA is a nonparametric method for comparing several related samples by looking at the order of responses rather than their exact values. The null hypothesis states that there is no treatment effect, which means the ranking of responses across the treatment conditions within each subject is not systematically different. Put differently, within each subject all possible patterns of rankings across the conditions are equally likely, so the distribution of ranks is the same across conditions. If the null holds, the average rank for every condition should be the same, and any observed differences are due to random variation. This focus on ranks and patterns of order distinguishes Friedman's test from tests that compare means (which would be about equal means) or tests concerned with variances or proportions.

Friedman’s ANOVA is a nonparametric method for comparing several related samples by looking at the order of responses rather than their exact values. The null hypothesis states that there is no treatment effect, which means the ranking of responses across the treatment conditions within each subject is not systematically different. Put differently, within each subject all possible patterns of rankings across the conditions are equally likely, so the distribution of ranks is the same across conditions. If the null holds, the average rank for every condition should be the same, and any observed differences are due to random variation.

This focus on ranks and patterns of order distinguishes Friedman's test from tests that compare means (which would be about equal means) or tests concerned with variances or proportions.