Thank you Gang, that is very helpful, will check it out. I agree on the headache part, though.
Just one last question in relation to the 1 vs. 234 contrasts. For each subject I already have these contrasts from a previous ANOVA. If I write a script (one for each contrast) where I include these contrast subbriks for each subject, could I, for conditions 234, include covariates which are the average of the 3 conditions ((2+3+4)/3), and then do the subtraction 1 - average(234)?
Thanks again,
Hedvig.