Hello
I have an experiment with 9 conditions and i want to see the overall effect of 7 of these conditions. I used the -GLT option on 3dDeconvolve with a multiple linear combination (7) to create an omnibus F stat but now need to put a sign on it to see what the direction of activation is. I used the script :
3dcalc -fscale \
-prefix signF \
-a52 Group+tlrc \
-b39 Group+tlrc \
-c41 Group+tlrc \
-d42 Group+tlrc \
-e43 Group+tlrc \
-f45 Group+tlrc \
-g47 Group+tlrc \
-h49 Group+tlrc \
-expr 'a*step(step(b)+step(c)+step(d)+step(e)+step(f)+step(g)+step(h))' \
where a=the f stat and b-h are the COEFS for each of the individual conditions that i would like to include.
However, the above script only gives me positive values and not the negative ones that one would associate with deactivity.
Could you please advise me on where the above script went wrong ?
Many thanks
Carl
