If I understand you properly, you have a patient and a control
subject. Then, you are putting the two images into a t-test.
The problem is that the error term is 0. The data is fully explained
by your design matrix (SPM.xX.X) and the statistics can not be
computed. There is no way to asses the significance in this design.
Thus, as has been said before, you can not not compare subject A to
subject B. Instead, you want to compare a patient (or set of patients)
to a set of controls. If you do not have a set of controls, then you
need to collect them.
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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2011/6/28 冰鳍 <[log in to unmask]>:
> Hello everyone,
> I am studying Voxel-based analyses(VBA) of DTI with SPM8,
> but I have only one heath person data. I had to modify some area of this
> data in order to imitate a patient data. I have two data now and each data
> has dimension of 256 256 50.
> When I estimate the SPM file after use “Two-sample t-test”
> ,the error singal is :"Please check your data There are no significant
> voxels". I have tried many methods but the message box still jump out.
> Could "Two-sample t-test" estimate only two groups datas?
> I will feel grateful if you can answer my question. Thank
> you!
>
>
>
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