Hi,
I’m making contrasts, and my 6 conditions are as follows: #1 female approach #2 male approach #3 female withdraw #4 male withdraw #5 car approach #6 car withdraw
If I want to create the contrast all-approaching-things minus fixation, I’m dealing with #1 female approach, #2 male approach, and #5 car approach. When I’m making the contrasts with mkcontrast, if I do (-a 1 -a 2 -a 5) that’s not what I want, because Matlab then weights each of them as .333. What I really want is for the car’s weight to equal the combined face’s weight to account for the 2 types of genders but only 1 type of car. Would it be correct to manually weight it as: ( .25 .25 0 0 .5 0)? I’m pretty sure that’s correct, but I just wanted to double check.
Thanks, Stephanie
Stephanie N. DeCross Clinical Research Coordinator Psychiatric Neuroimaging Research Program Martinos Center for Biomedical Imaging Massachusetts General Hospital 149 13th Street, Charlestown, MA 02129 Phone: 617-724-3283 Fax: 617-726-4078