why not a continuous model? what model do you want to use?
Xie, Hong wrote:
Thanks a lot. This scrip seemly describes F-test or T-test. In my
study, I want to analyze the correlationship between patient's
cortical thickness and pain scale (from 0 to 6). After I create data
table. Qdec automatically put pain scale into continuous variable
category. Actually, pain scale is ordinal variable, not continuous
variable. Different correlation model should be used. How should I do
it by qdec?
I very appreciate your help.
Hong Xie
------------------------------------------------------------------------
*From:* Douglas N Greve [mailto:gr...@nmr.mgh.harvard.edu]
*Sent:* Mon 1/12/2009 3:11 PM
*To:* Xie, Hong
*Cc:* freesurfer@nmr.mgh.harvard.edu
*Subject:* Re: [Freesurfer] Qdec correlation analyses
Not with QDEC, but you can write your own FSGD, See
https://surfer.nmr.mgh.harvard.edu/fswiki/FsgdExamples
Xie, Hong wrote:
> Hello,
> Thank you for answering me. I searched mailing list and read this
> answer email:
> /I see that group.levels has four levels. Unfortunately, right now
> qdec only supports two levels for a discrete factor. One the features
> in the works is to increase this./
> /Nick Schmansky
> Wed, 27 Feb 2008 11:08:10 -0800/
> Is this question still here? I have a five levels discrete factor. Can
> I run correlation statistic by Qdec?
> Thanks again
> Hong Xie
>
> ------------------------------------------------------------------------
> *From:* Douglas N Greve [mailto:gr...@nmr.mgh.harvard.edu]
> *Sent:* Thu 1/8/2009 4:40 PM
> *To:* Xie, Hong
> *Cc:* freesurfer@nmr.mgh.harvard.edu
> *Subject:* Re: [Freesurfer] Qdec correlation analyses
>
>
> It has to be interpreted as a continuous variable. The test is done
> using a t-test inside the glm. This reduces to a Pearson if there is
> only one variable and no intercept (which it is not).
>
> doug
>
> Xie, Hong wrote:
> >
> > Hello, freesurfer group,
> >
> >
> >
> > I have run qdec for comparing thickness between two groups. When qdec
> > does a correlation analyses for thickness versus a second variable: 1)
> > Does the second variable have to be a continuous interval variable or
> > 2) can the second variable be an ordinal variable with more than 2
> > levels? In the case of the correlation between two continuous
> > variable, is the test a Pearson correlation? If 2) is possible, is the
> > correlation a Spearman correlation?
> >
> > Thank for your help,
> >
> >
> >
> > Hong Xie
> >
> >
------------------------------------------------------------------------
> >
> > _______________________________________________
> > Freesurfer mailing list
> > Freesurfer@nmr.mgh.harvard.edu
> > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
>
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