Hi,

I have a question related to setting up the FSGD file for my analysis. Specifically, I’m looking into the effects of hormone levels on the brain in a single group (i.e., not comparing different classes). My model includes both continuous and categorical covariates.

From what I’ve gathered, most examples on the FreeSurfer website focus on group comparisons, which isn't the focus of my analysis. Therefore, I’ve set up an FSGD file with only one class (see the attached screenshot for reference). In this file:

• Variables like soft_A, soft_B, soft_C, child_raceMixed, and child_raceWhite are categorical covariates.

• Since these are covariates and not grouping factors, I haven’t created separate classes for them.

I believe this approach is appropriate, but I wanted to confirm whether that understanding is correct.

Additionally, regarding the contrast file:

• My contrast vector is 0 1 0 0 0 0 0 0 0 0 0, where the number of elements matches the number of variables in my model (including the intercept).

• As I’m specifically interested in the effect of E2_mean, I’ve set its position to 1 and all others (including covariates and intercept) to 0.

Is this the correct way to set up the FSGD and contrast files for this type of single-group analysis?

Thank you in advance for your guidance.

Best,
Muskan