Hey AFNI-experts,

We are using 3dMVM for factorial analysis. In the current experiment we have 2 factors: Order (P1,S1) and Event(P,S). This is an event P or S happening and the order is which one happened first. This is of course to balance the experiment, if the order matters. The table looks something like:

```
Subj Order Event InputFile \
s1 S1 S s1+tlrc'[S_beta]' \
s1 S1 P s1+tlrc'[P_beta]' \
s2 P1 S s1+tlrc'[S_beta]' \
s2 P1 P s1+tlrc'[P_beta]' \
```

I.e. subjects 1 got event S first and then P. Subjects 2 got event P first and then S.

Now we want to add a qualitative variable. If it was age it would be simple:

```
Subj Order Event Age InputFile \
s1 S1 S 24 s1+tlrc'[S_beta]' \
s1 S1 P 24 s1+tlrc'[P_beta]' \
s2 P1 S 30 s1+tlrc'[S_beta]' \
s2 P1 P 30 s1+tlrc'[P_beta]' \
```

But we now have a quantitative measure per condition. I.e. we have a rating from when the subject experiences event S and one for event P. Would I use 2 different q-vars and leave every other empty or can the q-var vary across the events?

Suggestion1:

```
Subj Order Event Q_rating InputFile \
s1 S1 S 10 s1_s+tlrc'[S_beta]' \
s1 S1 P 8 s1_p+tlrc'[P_beta]' \
s2 P1 S 2 p1_s+tlrc'[S_beta]' \
s2 P1 P 7 p1_p+tlrc'[P_beta]' \
```

Suggestion2:

```
Subj Order Event Q_ratingS1 Q_ratingP1 InputFile \
s1 S1 S 10 s1_s+tlrc'[S_beta]' \
s1 S1 P 8 s1_p+tlrc'[P_beta]' \
s2 P1 S 2 p1_s+tlrc'[S_beta]' \
s2 P1 P 7 p1_p+tlrc'[P_beta]' \
```

Suggestion 1 seems most reasonable but can the q-var have different values for the same subject within the same q-var? What we want to find out is if the subject rating is co-varying with the betas in some brain region taking the factors into account.

Thanks!