DRC SPM wrote:
> Hi all,
>
> I think this is an spm bug -- has anyone got a paired t-test to work?
This bug has been fixed in revision 456.
Best,
Will.
> I get the same error you describe on several different data sets.
> (spm5 rev 411, Matlab 7.0.1 r14)
>
> To get a simple paired t-test, you could just do a one-sample t-test
> on difference images (that you'll need to create yourself).
>
> I used avwmaths from FSL to create these, and spm5 was then able to
> perform a single-sample test with results that looked right.
>
> e.g. avwmaths A1.nii -sub B1.nii diff1.nii will give diff1 = A1 - B1
>
> (http://www.fmrib.ox.ac.uk/fsl/ though you could probably do this
> within Matlab/SPM)
>
> Best,
> Ged.
>
> On 16/02/06, Woodard, John <[log in to unmask]> wrote:
>
>>I'm trying to analyze a series of PET scans using the paired t-test analysis
>>option in SPM 5. There are 2 scans per patient, pre-drug and post-drug. The
>>design matrix appears to be appropriate, but when I try to estimate, I get
>>the following:
>>
>>
>>
>>
>>
>>SPM5: spm_spm (v$Rev: 301 $) 16:37:45 - 16/02/2006
>>
>>========================================================================
>>
>>
>>
>>SPM5: spm_spm (v$Rev: 301 $) 16:37:48 - 16/02/2006
>>
>>========================================================================
>>
>>Initialising parameters : ...initialised
>>
>>
>>
>>Plane 1/69 , block 1/1 : ...done
>>
>>Plane 2/69 , block 1/1 : ...done
>>
>>
>>
>>… …
>>
>>
>>
>>Plane 68/69 , block 1/1 : ...done
>>
>>Plane 69/69 , block 1/1 : ...done
>>
>>Temporal non-sphericity (over voxels) : ...REML estimation
>>
>>??? Error using ==> plus
>>
>>Matrix dimensions must agree.
>>
>>
>>
>>Error in ==> spm_reml at 84
>>
>> C = C + Q{i}*h(i);
>>
>>
>>
>>Error in ==> spm_spm at 860
>>
>> [V,h] = spm_reml(Cy,xX.X,xVi.Vi);
>>
>>
>>
>>Error in ==> spm_spm at 299
>>
>> spm_spm(SPM);
>>
>>
>>
>>??? Error while evaluating uicontrol Callback.
>>
>>
>>
>>
>>
>>
>>
>>Any ideas will be greatly appreciated!
>>
>>
>>
>>Best regards,
>>
>>
>>
>>John
>>
>>
>>
>>John L. Woodard, Ph.D.
>>
>>Associate Professor of Psychology
>>
>>Rosalind Franklin University of Medicine and Science
>>
>>3333 Green Bay Rd.
>>
>>North Chicago, IL 60064
>>
>>Voice: 847-578-3311
>>
>>Fax: 847-578-8765
>>
>>e-mail: [log in to unmask]
>>
>>
--
William D. Penny
Wellcome Department of Imaging Neuroscience
University College London
12 Queen Square
London WC1N 3BG
Tel: 020 7833 7475
FAX: 020 7813 1420
Email: [log in to unmask]
URL: http://www.fil.ion.ucl.ac.uk/~wpenny/
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