Friedman Analysis of Variance by Ranks

1 Continuous Dependent Variable with non-normal distribution

1 (Multi-Level) Categorical Independent Variable

	Task Completion time
Subject	Interface 1	Interface 2	Interface 3
1	12.9	16	4
2	5.7	7.5	4.3
3	16	16	5
4	14.3	15.7	5.3
5	2.4	13.2	4.9

The Friedman Analysis of Variance is the non-parametric version of repeated measures ANOVA. Friedman Analysis of Variance is applied under the same conditions as repeated measures ANOVA, except that the dependent variable need not be normally distributed for Friedman Analysis of Variance.

Values to report:

· Degrees of freedom

· Average rank correlation

· p value

· (optional) Chi square distribution