The limitation of the flexible factorial is to look at the group
comparisons of single levels of a factor or the average of a factor.
In your design you have BS1 (group), WS1 (type), WS2 (level).
Using the flexible factorial, you can only investigate the
within-subject effects (there are now numerous posts on this issue).
Between-subject effects require a separate model.
You can look at BS1*WS1, BS1*WS2, BS1*WS1*WS2, WS1, WS2, WS1*WS2
effects. You can also compare any difference between levels of a
factor or group differences of difference between levels of a factor.
These are all within-subject effects.
You wouldn't be able to look at BS1 effects on the mean of WS1
(average of movement type) or WS2 (average of movement level), nor any
level of WS1 (e.g movement 1) or WS2 or individual level (e.g.
movement 1, level 3) because these would be between-subject effects.
To test these, you'll want to use GLM Flex or construct separate
two-sample t-tests.
Hope this helps.
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
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On Wed, Apr 24, 2013 at 5:49 PM, Emily Sievers <[log in to unmask]> wrote:
> Hi-
>
> I have a question specific to my experimental design - and whether a
> flexible factorial design is possible and/or appropriate for analysis.
>
> In my design, I have two groups of subjects (clinical & control).
>
> The stimuli are somewhat complicated. Participants view videos of actions of
> two types that are all performed at three levels of movement. I would like
> to explore the effects of action type and movement level for each group and
> also compare my groups. I would also like to look at possible interactions
> between type and level.
>
> A colleague suggested that I explore the option of using a flexible
> factorial design, and I am wondering if this would be an appropriate and
> possible option (without becoming too muddled or uninterpretable).
>
>
> Thank you-
>
>
>
>
> Emily
>
>
> --
> Emily Sievers
> Graduate Student
> NeuroCognitive Development Lab
> Center for Mind and Brain
> 202 Cousteau Place, Suite 250
> Davis, California 95618
> (530) 747-3808
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