Kruskal Wallis Formula. It is considered to be the non parametric equivalent of the one way anova. H 1 2 n n 1 r 1 2 n 1 r 2 2 n 2 r k 2 n k 3 n 1 h frac 12 n n 1 left frac r 1 2 n 1 frac r 2 2 n 2 cdots frac r k 2 n k right 3 n 1 h n n 1 12.
P value 1 cdf χ 2h df p value 1 cdf χ 2h adj df for small samples minitab recommends that you use exact tables. Ssbg r n n 1 12. Like most non parametric tests you perform it on ranked data.
A kruskal wallis test is used to determine whether or not there is a statistically significant difference between the medians of three or more independent groups this test is the nonparametric equivalent of the one way anova and is typically used when the normality assumption is violated.
For 3 1 degrees of freedom and an alpha level of 05 the critical chi square value is 5 9915. Allen wallis or one way anova on ranks is a non parametric method for testing whether samples originate from the same distribution. Ssbg r n n 1 12. The kruskal wallis test does not assume normality in the data and is much less sensitive to outliers than.
