Hello,

I have a question about how to interpret the results from 3dANOVA2. I running a repeated measures anova (i.e., 3dANOVA type 2) with 4 levels of factor A and 6 subjects, i.e. 6 levels for factor B. Here is my analysis command:

3dANOVA2 -type 3 -alevels 4 -blevels 6 \
-dset 1 1 subj1-D1+tlrc \
-dset 1 2 subj2-D1+tlrc \
-dset 1 3 subj3-D1+tlrc \
-dset 1 4 subj4-D1+tlrc \
-dset 1 5 subj5-D1+tlrc \
-dset 1 6 subj6-D1+tlrc \
-dset 2 1 subj1-D2+tlrc \
-dset 2 2 subj2-D2+tlrc \
-dset 2 3 subj3-D2+tlrc \
-dset 2 4 subj4-D2+tlrc \
-dset 2 5 subj5-D2+tlrc \
-dset 2 6 subj6-D2+tlrc \
-dset 3 1 subj1-D3+tlrc \
-dset 3 2 subj2-D3+tlrc \
-dset 3 3 subj3-D3+tlrc \
-dset 3 4 subj4-D3+tlrc \
-dset 3 5 subj5-D3+tlrc \
-dset 3 6 subj6-D3+tlrc \
-dset 4 1 subj1-D4+tlrc \
-dset 4 2 subj2-D4+tlrc \
-dset 4 3 subj3-D4+tlrc \
-dset 4 4 subj4-D4+tlrc \
-dset 4 5 subj5-D4+tlrc \
-dset 4 6 subj6-D4+tlrc \
-fa Drugs \
-amean 1 D1 \
-amean 2 D2 \
-amean 3 D3 \
-amean 4 D4 \
-adiff 1 2 D1-D2 \
-adiff 1 3 D1-D3 \
-adiff 1 4 D1-D4 \
-adiff 2 3 D2-D3 \
-adiff 2 4 D2-D4 \
-adiff 3 4 D3-D4 \
-bucket ANOVA_results

My question is about the -fa option, and how that relates to the results of the 6 -adiff options.

1) Does the -fa option for Drugs test the whether or not there is alot at least one difference among the 4 level means?

2) If so, do the -adiff options represent s form of a post-hoc test (similar to a Tukey's HSD test), to see which levels significantly differ based on the main effect for Factor A

3) Would the activation maps for the main effect for Factor A correspond to the adiff activation maps? It appears that they don't when you set the set the p values (say p = 0.05) equal for the adiff T-statistic and the -fa F-statistic. I see activated areas in the contrast activation map that show up at p = 0.05, that don't show up in the -fa F-statistic activation map at p = 0.05.

Your help would greatly be appreciated.

Thanks