I’ve analyzed a flexible factorial design with the factors:
- Subject (36 subjects)
- Condition (3)
- Group (2)
Analysis and results look fine.
Now I want to include a covariate (the subjects performance in condition 1, 2, 3). I tried to enter the vector as a 3*36 vector:
Subject 1: performance condition 1 / performance condition 2 / performance condition 3
Subject 2: performance condition 1 / performance condition 2 / ……………………………
However, evaluation failed. Because the spm-help mentions to enter the covariates by subject I created 36 covariates and entered the 3 values for each subject. However, I get the following error message:
Failed 'Factorial design specification'
Index exceeds matrix dimensions.
[…] (v4178), function "spm_design_within_subject" at line 81.
[…] (v4185), function "spm_run_factorial_design" at line 508.
Where is my mistake?
Thanks in advance & best regards,