Hi,
You either need to split the covariates as you suggested or only use a
single variance group - your design is not separable as it is
hth
Christian
On 1 Feb 2009, at 23:00, Vina Goghari wrote:
> Hi, Thanks. I used version 5.98 and the error was: Warning - design
> matrix uses different groups (for different variances), but these do
> not contain "separable" EVs for the different groups (it is
> necessary that, for each EV, only one of the groups has non-zero
> values).
>
> Vina
>
> Steve Smith wrote:
>> What FSL program are you running and what error are you getting?
>>
>>
>> On 31 Jan 2009, at 19:19, Vina Goghari wrote:
>>
>>> Hi FSL Group,
>>> Reading up on previous covariate inclusion in models I had thought
>>> the following model was doable but I am getting an error.
>>>
>>> I have three groups and three covariates I want to include (not
>>> super interested in seeing the effect of group so I thought I
>>> could enter it like this). Thus I coded it like this:
>>>
>>> Group1 Group2 Group3 AgeCovariate GenderCovariate
>>> ScannerVersionCovariate
>>> 1 1 0 0
>>> 34 1 1
>>> 1 1 0 0
>>> 45 2 2
>>> 1 1 0 0
>>> 52 1 2
>>> 2 0 1 0
>>> 34 2 2
>>> 2 0 1 0
>>> 76 2 2
>>> 2 0 1 0
>>> 24 2 1
>>> 3 0 0 1
>>> 19 2 1
>>> 3 0 0 1
>>> 9 1 1
>>> 3 0 0 1
>>> 35 1 1
>>>
>>> Do I need to split the each covariate into 3 columns one per group?
>>>
>>> Thanks,
>>> Vina
>>>
>>
>>
>> ---------------------------------------------------------------------------
>> Stephen M. Smith, Professor of Biomedical Engineering
>> Associate Director, Oxford University FMRIB Centre
>>
>> FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
>> +44 (0) 1865 222726 (fax 222717)
>> [log in to unmask] http://www.fmrib.ox.ac.uk/~steve
>> ---------------------------------------------------------------------------
_______________________________________________
Christian F. Beckmann, DPhil
Senior Lecturer, Clinical Neuroscience Department
Division of Neuroscience and Mental Health
Imperial College London, Hammersmith Campus
Rm 419, Burlington Danes Bldg, Du Cane Road, London W12 0NN, UK
Tel.: +44 (0)20 7594 6685 --- Fax: +44 (0)20 7594 6548
Email: [log in to unmask]
http://www.imperial.ac.uk/medicine/people/c.beckmann/
Senior Research Fellow, FMRIB Centre
University of Oxford
JR Hospital - Oxford OX3 9DU
Tel.: +44 (0)1865 222551 --- Fax: +44 (0)1865 222717
Email: [log in to unmask]
http://www.fmrib.ox.ac.uk/~beckmann
|