Is Wilcoxon test appropiate for the comparison of large, independent, nonnormal datasets?
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Hi all!
I am using 'ranksum' function (Wilcoxon test) to compare two independent, nonnormal, large data sets. However, p-value is 0 I think because of the effect of large data size. Any other test statistics that may handle such a large population analysis?
Thanks in advance :)
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Star Strider
on 17 Aug 2024
Since we’re likely discussing the lognormally distributed data you previously described, and since this is an unpaired comparision, ranksum is appropriate. A p value of 0 is an excellent result if you want to demonstrate that any two results ar different, since that indicates that they are and that the calculated probability is below the ability of floating-point arithmetic to calculate any other value ().
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Star Strider
on 17 Aug 2024
As always, my pleasure!
Using ranksum is correct for a comparison of two vectors. I would use multcompare specifying 'friedman' in the ‘stats’ structure to do multiple comparisons. For 'CriticalValueType', I was always taught to use 'scheffe', however that may reflect the comparisons I was doing.
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