Hi Gonzalo and Alexander,
I have the same problem but I do not think it is because I don't have enough
pairs of scans (I have 22 in group 1 and 37 in group 2). If it is simply that
there is nothing to be detected in the data, then the same error
message should
occur when doing a 2 sample t test on the same group of people (22 in group 1
and the same 22 in group 2). However, this is not the case; spm still
estimates
and runs results.
I am still struggling with this error message too and would appreciate
any help
if anyone knows about it.
Thanks
Sien
Quoting Alexander Hammers <[log in to unmask]>:
> Dear Gonzalo,
>
>
> How many pairs of scans do you have (pairs of patients, pairs of
> controls)? You may simply not have the statistical power to detect
> anything.
>
> All the best,
>
> Alexander
>
>
> ---------------------------------
> Alexander Hammers, MD PhD
>
>
>
> NEW Affiliation:
> Chair in Functional Neuroimaging
> Fondation Neurodis
> http://www.fondation-neurodis.org/
>
> NEW Postal Address:
> CERMEP – Imagerie du Vivant
> Hôpital Neurologique Pierre Wertheimer
> 59 Boulevard Pinel
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>
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> [log in to unmask];[log in to unmask]
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>
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> ---------------------------------
> Other affiliations:
>
> Visiting Reader; Honorary Consultant Neurologist
> Division of Neuroscience and Mental Health, Faculty of Medicine
> Imperial College London
>
> Room 243, Cyclotron Building
> Hammersmith Hospital, DuCane Road, London W12 0NN
>
> and
>
> Honorary Reader in Neurology; Honorary Consultant Neurologist
> Department of Clinical and Experimental Epilepsy
> National Hospital for Neurology and Neurosurgery/ Institute of Neurology,
> UCL
> 33 Queen Square, London WC1N 3BG
>
> On 6 Oct 2009, at 02:01, Gonzalo Rojas wrote:
>
>> Hi:
>>
>> I am working with a paired T-test study to compare two PET
>> aquisitions of one patient... In the "Estimate" process I got the error
>> "Please check your data. There are no significant voxels"... I used the
>> default values of the Paired t-test design...
>>
>> Sincerely,
>>
>>
>> --
>> Gonzalo Rojas Costa
>> Department of Radiology
>> Las Condes Clinic
>> Lo Fontecilla 441, Las Condes, Santiago, Chile.
>> Tel: 56-2-2105170
>> Cel: 56-9-97771785
>> www.clc.cl
>
>
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