I was just responding to your previous message while your update came in! Yes, you already found out the problem: when MEdu = 2, there are no Female subjects in the LR group:
Sex
Group Female Male
HR 7 12
LR 0 3
> Is there a way to still include Sex as a factor without the program erroring out?
Unfortunately you cannot have both Sex and MEdu in the same model using 3dMVM, but I'm not sure why the model 'Group+Sex' failed. If you want me to dig it deeper, I may have to ask you to share a testing dataset for diagnosis.
On the other hand, try using 3dttest++ with -1/1 coding for Sex ang MEdu, and it may work in this case.
Gang
Edited 2 time(s). Last edit at 07/24/2021 10:26AM by Gang.