The first 15 rows correspond to the setosa species, so I run:
p.adjust(wilcox_p$p[1:15], method = "BH")
The first three p-values are 0.9313636, 0.9313636, 0.1950000. This compares with 0.931, 0.931, 0.192 from wilcox_test. Any thoughts on why this is?
As far as I understand, multiple testing correction is only done within a group e.g. for comparisons made within a species in this example. Would you not also want to correct for the fact that you are testing multiple species?
Hi @kassambara,
I am getting slightly different p-values if I
p.adjust.method
withinwilcox_test
or runp.adjust
afterwards and I am just trying to understand why.The first 15 rows correspond to the setosa species, so I run:
The first three p-values are 0.9313636, 0.9313636, 0.1950000. This compares with 0.931, 0.931, 0.192 from
wilcox_test
. Any thoughts on why this is?As far as I understand, multiple testing correction is only done within a group e.g. for comparisons made within a species in this example. Would you not also want to correct for the fact that you are testing multiple species?
So do you recommend:
Best wishes, Lucy