The Kruskal-Wallis test statistic can be approximated by a chi-squared distribution with k− 1 degrees of freedom (where k is the number of populations)whenever the sample sizes are all greater than or equal to:
A)5
B)10
C)30
D)None of these choices.

Question

Quizplus · Accepted Answer

The approximation of the Kruskal-Wallis test statistic by a chi-squared distribution with k− 1 degrees of freedom assumes that the data are reasonably well-behaved and the sample sizes are not too small. The general rule of thumb is that the sample sizes should be at least 5, but some statisticians recommend a higher cutoff of 10 or even 30 in some cases. However, there is no need to exceed a sample size of 5 for the Kruskal-Wallis test to be approximated with the chi-squared distribution. Therefore, the best choice is A, which is the smallest cutoff value that satisfies the assumption of the approximation.

The Kruskal-Wallis Test Statistic Can Be Approximated by a Chi-Squared