Dear SPM Experts,I´m new to SPM8-VBM and want to compare two groups. Unfortunately these 2 groups (n>200) are only matched for age (p=0.709) but not for sex (because there are not enough women in the control).Therfore my control group (0) contains about 67% women and my case group (1) only 15.4%! My design parameters where specified for two-sample t test with the VBM8-Manual (http://dbm.neuro.uni-jena.de/vbm8/VBM8-Manual.pdf). I am looking for differences in GM caused by alcohol consumption (group 0 more than group 1).My Results show very significant (FWE corrected with p=0.05) changes in brainmorphometry in several regions, where group1 has less GM than group0. How can I change my design to avoid false results that came only from gender difference and not the one that i´m looking for (alcohol)?(I thought about setting sex as covariate but be not sure and don´t know how should the parameters for "interaction" and "centering" be set and also the contrast vector in "results")Thanks in advance.
