Group GLM Analysis (Volume)
When you perform a group analysis, you are looking for effects of the task across the population. Now decide if you are running a Random Effects or Weighted Random Effects or Fixed Effects Analysis.
Random Effects (RFx, OLS) (Volume) This is a program for intersubject averaging using a random-effects model, by computing one number for each subject (at each voxel) based on the contrast matrix.
Weighted Random Effects (WRFx, WLS) (Volume) In a real experiment, some subjects are noisier than others, and it is a good idea to take this into account since we have information about how noisy a subject is through the lower-level analysis. In weighted least squares (WLS), this is handled by weighting each subject by the inverse of their noise (i.e., noisier subjects get lower weight). The first-level noise variances (tal.cesvar.nii) are passed with the --wls option.
Fixed Effects (FFx) (Volume) This is a program for intersubject averaging using a fixed effects model, where data from all subjects are treated as if they came from a single subject.