I have a four distributions: A,B,C,D. A has 55 observations, B has 30, C has 110, and D has 13. the four distributions are non normal and have unequal variance.
I would like to test to see if the means between any of the four are significantly different. I as wondering what is a robust way of testing this.
I came across doing a permutation test. However, in the cases that I saw, this was done between two distributions. Would a permutation test be appropriate in my case?