we are doing VBM using the VBM5 toolbox and we are doing an ANOVA with 4
groups. i was wondering what is the correct way to specify the contrast when
we want to compare one group against the other 3 groups. We are inclined to
use the following weights for our contrast
[-1 0.33 0.33 0.33]
is this right? will decreasing the weight of each group to 0.33 change the
signal and variance of that group in anyway?
Is there a better way to specify this contrast?