I have 23 subjects, and I want to make comparisons of the distribution of a measurement (with non-normal distribution) across several categories. In one category there are 3 groups (n1= 3, n2= 10, n3= 10), and another category 4 groups (n1= 1, n2=3, n3=4, n4=15). I'm using SPSS 20 to undertake Kruskal Wallis testing to make comparisons for each category.

I've carried out the tests, but I'm concerned of their appropriateness. Does SPSS 20 allow for such small minimum group sizes for this?

If it does, would I be right in thinking though that such small, unequal group sizes within categories means the study is likely to be underpowered to determine a true difference between the distributions of group measurements?

Any help much appreciated!!

I've carried out the tests, but I'm concerned of their appropriateness. Does SPSS 20 allow for such small minimum group sizes for this?

If it does, would I be right in thinking though that such small, unequal group sizes within categories means the study is likely to be underpowered to determine a true difference between the distributions of group measurements?

Any help much appreciated!!

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