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Anne,

A couple of quick comments:

(1) You'd need subject numbers as a factor. When you make the model, make sure the model includes all three factors in the design matrix (group, capacity, subjects);
(2) Condition is not a factor since it only has one level, so you have a 2x2 design.
(3) You can only intrepret the group*task and task effects. The group effect or single condition effects or group differences for a single condition are invalid. This is due to the use of a single error term in SPM. If you want to interpret the group effects, you need to either: (a) use GLM Flex; or (b) average the capacity measures for each subject and then use a one-way ANOVA of the averages.

I would recommend GLM Flex since its a single model, but for the 2x2 design you can use flexible factorial. Just remember the points under #3.

Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Postdoctoral Research Fellow, GRECC, Bedford VA
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
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On Wed, May 2, 2012 at 10:37 AM, Anne Vellage <[log in to unmask]> wrote:
Hello,


I am trying to put together an ANOVA of one group with two measuring time points (repeated measure). I have the factor condition with one level and a within factor capacity (2 levels)

Half of the group has a low capacity and the other half a high capacity. So its something like a 2x2x1 design ;)

Im interestet in the interactioneffect of capacity and group in one special condition.

I read the Gläscher & Gitelman Scribt but found no idea for a condition factor with one level and an additional within factor (capacity).

I have problems with setting up the design. It should be something like:

Factor 1 = subjects
Factor 2 = group (2)
Factor 3 = Capacity (2)
Factor 4 = Condition (1)

Group   Capacity  Condition
   1            1                1
   1            1                1
   1            1                1
   1            1                1
   1            2                1
   1            2                1
   1            2                1
   1            2                1
   2            1                1
   2            1                1
   2            1                1
   2            1                1
   2            2                1
   2            2                1
   2            2                1
   2            2                1

How do I have to set up the factors? Is an ANOVA  possible with a factor "condition" with only one level? Is the flexible factorial thr right way to do the analysis or is there a better way for within and between factors analysis?

I would be grateful for help,

Anne