Sample size assessment for two-way ANOVA with repeated measures with GPOWER (or other software?)

Cagri

New Member
#1
I’m trying to assess the sample size for the interaction of two within subjects factors -for a two-way ANOVA with repeated measures analysis
Design: In a single sample, participants; On the first week learn 36 words in 3 different sets (12 from set A, 12 from set B, 12 from set C) and take a nap, and are retested for their memory of these words. Second week, they again learn 36 words (12 from set A, 12 from set B, 12 set C) and stay awake, and are retested for their memory of these words.
We’re trying to find out if nap vs. staying awake makes a difference in remembering between the 3 set of words at retest.
So there are two within subjects factors: one with 2 levels (nap vs. wake) and the other with 3 levels (Set A, Set B, Set C).
Question: In GPower (v 3.1.9.2) menu, there are options to calculate sample size for within subjects factors and between subjectsxwithin subjects interaction. However, I couldn’t see calculation for the interaction of two within subjects factors. Also, I wasn’t sure what to put in Groups and Measurement -There seems to be different answers in statistics forums.