Dear SPMers: I tried to use basic model from SPM to creat two-sample t test for two groups' comparison, why the basic model shows "implicit mask(ignore zero's)?" before "explicit masking" for one model creation while not showing "implicit mask(ignore zero's)?" before "explicit masking" in another model creation? Thank you in advance Weiying __________________________________ Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. We finish. http://promotions.yahoo.com/new_mail