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Hello Jessica,
please see my inline reponses below.
Best regards,
Kersten
On Mo, 2019-12-02 at 02:48 +0000, Hua, Jessica wrote:
External Email - Use Caution Hi FreeSurfer Experts,
I used the longitudinal pipeline and analyzed my data using the univariate linear mixed effects models. I had a couple of questions:
- The model outputted the F and p values. How do I calculate the
effect size?
There are some standardized effect sizes for LME models described in the literature, but none are, as far as I know, included in the lme toolbox, so one would still need to implement them.
In my opinion, it's therefore easiest to express the magnitude of changes / differences in terms of unstandardized effect sizes, i.e. the beta coefficients estimated by the model.
- How do I plot my analyses? I would like to create a plot for
change in CC volume with eBAC. Below is my model:
Yij = ß1 + ß2(timeij) + ß3(eBACi) + ß4*estimated eBACi*timeij + ß5(genderi) ß6(intracranial volumei) + b1i + b2i(timeij) + eij.
That really depends on how your plot should look like, and may require some custom Matlab programming. For 'spaghetti'-style plots (i.e. a bunch of individual slopes), have you explored the 'lme_timePlot' function?
Thank you for your help!
Jessica
Jessica Hua, M.A. Cognitive and Emotional Control Lab Doctoral Candidate Clinical Psychology University of Missouri _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer