Hi Anderson,
thank you so much for your quick and very helpful response. I could finally understand how the interaction model works and why i don't need -D Option.
I have one more very important question though, i hope you can help me again with:
My question concerns both the group comparison and the interaction model of the Covariates of Interest.
1. FA-Group Comparison
I put this design matrix (and the contrast file below) in my last message to you:
G1 G2 Age(G1)Age(G2)Gen(G1) Gen(G2) RS(G1) RS(G2)
1 0 78 0 2 0 11 0
1 0 65 0 2 0 24 0
1 0 73 0 1 0 3 0
0 1 0 78 0 1 0 13
0 1 0 68 0 1 0 25
0 1 0 60 0 2 0 12
and the contrast file:
1 -1 0 0 0 0 0 0
-1 1 0 0 0 0 0 0
In my actual study i not only have Age Gender and one rating scale. I also have two more rating scales, two different cortisol-data
AND
fMRI-data to nine brain regions acquired under 4 different neuropsychological conditions (but in the same MRI session). To sum it up: 36 different fMRI-Co-variates of no Interest, each of which will get two EV’s as showed in the matrix above (same goes for the two cortisol data and the other two rating scales).
So far i did my group comparison (and Interaction-Analysis) with 5 different Designs:
1. corrected for: Age Gender Cortisol and the rating scales
2. corrected for: Age Gender and the fMRI-first condition
3. corrected for: Age Gender and the fMRI-second condition
4. corrected for: Age Gender and the fMRI-third condition
5. corrected for: Age Gender and the fMRI-fourth condition
But is it also possible to put everything in one design-matrix? Or would that be to many Co-Variates of no interest, which i want to correct for? Or would that affect or confound the statistics?
2. FA-Correlation- and FA-Interaction- Analysis:
In case it works to put all the parameters in one Matrix for Group comparison, can I use the same matrix (with a different contrast file of course) for the correlation and interaction-Analysis, which I explained in my previous message?
I hope you can help me with this issue as well, but in any way: Thanks a lot in advance!
I appreciate everything you can comment on!
Kind regards
Berel
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