help > Questions about ANCOVA models
Nov 20, 2023  03:11 PM | Elain Liao
Questions about ANCOVA models

Dear Colleagues

I have two between-subjects contrasts: Group A & Group B and two conditions: Pre- & Post-.


I  used CONN to do a Time*Group ANCOVA and added covariates of no interest (i.e Age, Education year, Baseline clinical score1, Baseline clinical score2).


Firstly, I selected


a)"Group A", "Group B", "Age of A&B", "Education Year of A&B", "clinical score 1", and "clinical score 2" in the subject-effects list, and entered a [1 -1 0 0 0 0 ] between-subjects contrast


b) 'Pre' and 'Post' in the conditions list and entered a [-1 1] between-conditions contrast


and then successfully got the significant group by scan interaction.


Now I wonder how to set the model to determine the simple main effects of conditions, simple main effects of group, main group effects, and main condition effects.


Take "simple main effects of conditions" for example,


is that correct that I select


a)"Group A", "Group B", "Age of A&B", "Education Year of A&B", "clinical score 1", and "clinical score 2" in the subject-effects list, and enter a [1 0 0 0 0 0; 0 1 0 0 0 0] between-subjects contrast


b) 'Pre' and 'Post' in the conditions list and enter a [-1 1] between-conditions contrast.


All your comments are highly appreciated,
Elaine

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TitleAuthorDate
Questions about ANCOVA models
Elain Liao Nov 20, 2023
Alfonso Nieto-Castanon Nov 25, 2023