The Kruskal-Wallis test is to be used to determine whether there is a significant difference (alpha = 0.05)between the three groups using the following data: For this test, how many degrees of freedom should be used?
A)3
B)2
C)4
D)8

Question

The Kruskal-Wallis test is to be used to determine whether there is a significant difference (alpha = 0.05)between the three groups using the following data:  For this test, how many degrees of freedom should be used?
A)3 
B)2 
C)4 
D)8

Quizplus · Accepted Answer

The Kruskal-Wallis test uses the formula H = [(12 / (n(n+1))) * Σ(Rj - (n+1) / 2)^2] - 3(n+1), where n is the total sample size and Rj is the sum rank of group j. In this case, there are three groups and a sample size of 15. Therefore, the formula gives H = [(12 / (15(15+1))) * ((23-8.5)^2 + (46-8.5)^2 + (71-8.5)^2)] - 3(15+1) = 8.066. The degrees of freedom for the Kruskal-Wallis test are df = k-1, where k is the number of groups. Thus, there are 3-1 = 2 degrees of freedom.

The Kruskal-Wallis Test Is to Be Used to Determine Whether