The output results for q-value of my 3ttest++ on resting state data with two groups (healthy volunteers vs patients), two visits combined, using resting state scans, does not match the results using the afni display.
I used this gen_group_command.py:
gen_group_command.py -write_script analysis_script.tt.100s_vs_300s_AllV_R2 -command 3dttest++
-set_labels 100s 300s
-Clustsim -prefix_clustsim Clust.100s_vs_300s_AllV_R2 -mask TSNR_brainmask_files/clip_count_group_brainTissueMask_tSNR10_Visit1.2+tlrc
and got the following results:
++ Smallest FDR q [1 100s-300s_Zscr] = 0.044138 <==========++++++++ @ p = .001, but q = .7157, L Anterior Cingulate Gyrus (BA 24) size 14 voxels
++ Smallest FDR q [3 100s_Zscr] = 1.13601e-10
++ Smallest FDR q [5 300s_Zscr] = 3.00011e-10
- Added 3 FDR curves to dataset
++ Output dataset ./ResultsA.tt.100s_vs_300s_AllV_R2+tlrc.BRIK
++ Output dataset ./Clust.100s_vs_300s_AllV_R2.resid.nii
- 2-sample test: results are 100s - 300s
As noted, the smallest FDR q was 0.044138. However, when I look at the results in afni, there are no significant results at q=.05 (or .04 or .06). The only significant result > 10 voxels at p=.001 (with a q=.7157) is a cluster of 14 voxels which does not meet the clust size min of 38 for alpha = .001 and p= .05.
I’m wondering why the 3dttest++ command found the smallest FDR q = .04413, but I can’t find anything significant at anywhere near that level using the afni display.