Dear all-
we have a paradigm where we have one main condition, three parametric modulators of the main condition (all numerical ones with values ranging from -2, 2, in case it matters) and one control condition. Our design is: Main, Main*modul1, Main*modul2, Main*modul3, Control. What is the best approach to get the effect of each of the modulators on the main condition?
Is it okey to subtract the control condition? In other words, is 0 1 0 0 -1 a valid contrast?
Or one should only use this one 0 1 0 0 0 to control for the effect of others regressors?
Thanks in advance!
Dimitrios and Giovanna
