I have a data for 322 items that are purchased between 2014 and 2018 by men and women. If I ran a Wilcoxon Signed-Rank test with a Benjamini-Hochberg correction on the items purchased by men and women over the five year purpose I find that 83% are significant (<= 0.05) and 17% are not significant (>0.05).
But if I then calculate the average purchases of men and women over the five year and run the test again, I find no significance whatsoever. I'm not sure which test I should use. Shouldn't the average also show significance?
One is a test over each item over the five years and the other is an average over all items in each year.