Thank you for your quick reply, Doug.
I apologize because I made a mistake when copying the post-hoc contrast in my previous message, and I sent the contrast for an analysis that compares the regression slopes of two groups for a particular covariate. I assume that the correct option for g1>g2 for my previous ANOVA design would be:
1 -1 0 0 0 0 0 0 0 0 0 0
Is that correct?
In addition to these three groups and these three covariates, I have scores of a neuropsychological test (NT) in all subjects. I would like to evaluate if there are different effects of this test on cortical thickness by diagnosis before testing whether two specific groups differ in the NT slopes (e.g., 0000000000001-10). Is there any way to do this?
Many thanks in advance,
Jose
----- Mensaje original -----
De: Douglas N Greve <greve@nmr.mgh.harvard.edu>
Fecha: Martes, 11 de Enero de 2011, 17:01
Asunto: Re: [Freesurfer] contrasts using DODS
A: Jose Luis Cantero Lorente <jlcanlor@upo.es>
CC: Freesurfer mailing list <freesurfer@nmr.mgh.harvard.edu>
> the 1st contrast looks correct. I'm not sure what you're trying
> to do
> with the 2nd contrast. This would be a test for g1>g2 on the 3rd
> covariate (essentially an interaction between g1/g2 and the 3rd
> cov). It
> would not be a post-hoc test because that's not the test you did
> in the
> first contrast.
>
> doug
>
> Jose Luis Cantero Lorente wrote:
> > Hello,
> >
> > we are analyzing cortical thickness data from three groups and
> want to
> > study whether there are between-group differences after
> removing the
> > effects of three covariates. We are assuming different
> intercepts and
> > different slopes (DODS) and would like to be sure that the
> contrasts
> > performed for the ANOVA and for the post hoc comparisons are
> correct:>
> >
> >
> > ANOVA
> >
> >
> > 1 -1 0 0 0 0 0 0 0 0 0 0
> >
> > 1 0 -1 0 0 0 0 0 0 0 0 0
> >
> >
> >
> > e.g., post-hoc analysis for testing group1 > group2
> >
> >
> > 0 0 0 0 0 0 0 0 0 0 0 0 1 -1 0
> >
> >
> >
> >
> >
> > I would appreciate your help with this matter.
> >
> >
> >
> > Best regards,
> >
> > Jose
> >
> >
> > ---
> > Jose L. Cantero, Ph.D.
> > Laboratory of Functional Neuroscience
> > Department of Physiology, Anatomy and Cell Biology
> > University Pablo de Olavide
> > Ctra. de Utrera, Km.1
> > 41013 - Seville
> > - Spain -
> > Phone: +34 954 977433
> > Fax: +34 954 349151
> > Email: jlcanlor@upo.es
> > http://www.upo.es/neuroaging/en/
> > ---------------------------------------------------------------
> ---------
> >
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>
> --
> Douglas N. Greve, Ph.D.
> MGH-NMR Center
> greve@nmr.mgh.harvard.edu
> Phone Number: 617-724-2358
> Fax: 617-726-7422
>
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---
Jose L. Cantero, Ph.D.
Laboratory of Functional Neuroscience
Department of Physiology, Anatomy and Cell Biology
University Pablo de Olavide
Ctra. de Utrera, Km.1
41013 - Seville
- Spain -
Phone: +34 954 977433
Fax: +34 954 349151
Email: jlcanlor@upo.es
http://www.upo.es/neuroaging/es/