Remove subject from the model and the flexible factorial setup. Subject CAN
only be AND MUST be included in within-subject designs. Your design is
purely between subjects.

When you specify subjects the error term goes to 0. When this happens, SPM
produces this message. There are several other potential causes as well
(e.g. no overlapping voxels in ALL subjects, using the same scan twice,
etc.), but this is why it appeared in this case.

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
Office: (773) 406-2464
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On Tue, May 10, 2011 at 3:11 PM, zhang sheng <[log in to unmask]> wrote:

> Dear all,
> I have a problem for the Flexible factorial analysis.
> In second level analysis, I tried to do a Flexible factorial analysis with
> two factors: "group" (e.g. patient vs. control) and "gender". So in the
> design, I have three factors: subject, group, and gender. As I have only one
> scan for each subject, the factor matrices should be [1 1] for group1 and
> male, [1 2] for group1 and female, [2 1] for group2 and male, and [2 2] for
> group2 and female for each subject (see attached file for design matrix)?
> However, when I estimated the model, I got an error message: *Please check
> * your *data*: *There* are *no significant voxels. *So, first, did I do
> something wrong with the model design? If I'm right, could someone tell me
> what happened for the estimating?
> Thanks, and any suggestion is highly appreciated!
> Sheng