I have done a two-way repeated-measures ANOVA with factor A having 3 levels and factor B having 5 levels. I am doing post hoc comparisons between all 3 levels of factor A within each of the 5 levels of factor B, resulting in 15 comparisons. I am not explicitly doing any post hoc comparisons between the levels of factor B.
Assuming I use Bonferroni to correct for alpha inflation (disregarding whether or not it is the best correction method) would I need to correct by the number of tests I am actually doing (15), or the number of all possible comparisons, i.e. 45, including the 30 comparisons between the levels of factor B within each level of factor A? I have seen different opinions on which of these comparisons should be regarded as a family.
Thanks in advance!