Hi Matthew,
If you have 3 (different) groups of subjects each with the same 2x2 factorial design, try using the full factorial model. SPM then automatically computes main effects and up to 3-way interactions.
You may also want to switch to SPM8.
Very best,
Martin
--
Martin Dietz
[log in to unmask]
On May 21, 2010, at 5:12 AM, Matthew Shane wrote:
> I'm trying to use the Flexible-factorial approach in SPM5 to conduct a 3 (Group) x 2 (Instruction) x 2 (Accuracy) mixed-model ANOVA. But I'm having a hard time isolating my conditions in my design matrix in a way to allow such a 3-way analysis to occur.
>
> Indeed, the main effect/interaction option within the Flexible Factorial design options only allows for the set-up of a 2 x 2 interaction. So I can create a Group x Instruction interaction and a Group x Accuracy interaction....but I'm having a hard time figuring out how to do the 3-way analysis.
>
> Is there a way to conduct such a 3-way analysis?
>
> Thanks all,
> Matt
|