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Hello Gwenaelle,

I am not sure what it means "if you're not dying for degrees of freedom".
How can i test it?

Thank you!

Patricia.

2010/11/25 Gwenaëlle DOUAUD <[log in to unmask]>

> Hi Patricia,
>
> I am not an authority on this, but Tom is, so I would take his word for it
> ;-)
> As he said, if you're not dying for degrees of freedom, then the first
> approach might be the best one, as then the other C & D groups' variance
> will not influence your results when comparing A & B...
>
> If you've got significant results already, you don't need the uncorrected
> p-values.
>
> Cheers,
> Gwenaelle
>
>
> De: Patricia Pires <[log in to unmask]>
> Objet: Re: [FSL] Re : [FSL] Glm
> À: [log in to unmask]
> Date: Jeudi 25 novembre 2010, 12h03
>
> Hello Gwenaelle,
>
> Thank you again...I chose the ANOVA because of some people told me it was
> more correct than t-test, but if you tell me it's ok for my model i'll
> choose 2 sample ttest unpaired, then. :)
>
> I have signifficant results with corrected option in randomise, is
> necessary run -x option in this case?
>
> Bests regards,
>
> Patricia.
>
> 2010/11/25 Gwenaëlle DOUAUD <[log in to unmask]<http:[log in to unmask]>
> >
>
> Hi Patricia,
>
> it looks ok to me, though I am not sure why you would choose to follow the
> second model rather than the first one based on the previous answer,
> especially if you're only looking at the contrasts between the healthy group
> and every other disease group... You might want to add the -x option in
> randomise to output the uncorrected p-values.
>
> Cheers,
> Gwenaelle
>
>
>
> --------------------------------------------------------------------
>
> Gwenaëlle Douaud, PhD
>
> FMRIB Centre, University of Oxford
> John Radcliffe Hospital, Headington OX3 9DU Oxford UK
>
> Tel: +44 (0) 1865 222 523 Fax: +44 (0) 1865 222 717
>
> www.fmrib.ox.ac.uk/~douaud
>
> --------------------------------------------------------------------
>
>
>
>