Hi there, 1. A followup question regarding contrasts in glmfit - when there are multiple contrasts, does that affect the degrees of freedom, or is each contrast tested separately? 2. When analyzing exported stats tables in SPSS, i can test hypothesis regarding specific regions without correcting for repeated measures across the whole brain. But the statistical power is much lower, and the volume or thickness is the average of the whole region, hence significant effects may not necessarily appear in glmfit. Is there a way of applying the glmfit to an ROI/label? thanks ilana
On 4/20/11 7:34 PM, Ilana Hairston wrote:
Hi there,
- A followup question regarding contrasts in glmfit - when there are
multiple contrasts, does that affect the degrees of freedom, or is each contrast tested separately?
There is not a correction for multiple contrasts, if that's what you mean. The DOF is the same regardless of how many contrasts you have.
- When analyzing exported stats tables in SPSS, i can test hypothesis
regarding specific regions without correcting for repeated measures across the whole brain. But the statistical power is much lower, and the volume or thickness is the average of the whole region, hence significant effects may not necessarily appear in glmfit. Is there a way of applying the glmfit to an ROI/label?
I'm not sure I understand. Do you want to analyze the stats table in glmfit? If so, you can use the --table option to specify the input (instead of --y; and don't spec --surf).
doug
thanks ilana
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Ilana Hairston ,PhD Research Assistant Professor 4250 Plymouth Rd. (rm 2439) Psychiatry Department, Addiction Research Center University of Michigan, Ann Arbor MI 48109-2700 Tel: 734-232-0232; Mobile: 650-906-8449
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Hi there, 1. A followup question regarding contrasts in glmfit - when there are multiple contrasts, does that affect the degrees of freedom, or is each contrast tested separately? 2. When analyzing exported stats tables in SPSS, i can test hypothesis regarding specific regions without correcting for repeated measures across the whole brain. But the statistical power is much lower, and the volume or thickness is the average of the whole region, hence significant effects may not necessarily appear in glmfit. Is there a way of applying the glmfit to an ROI/label? thanks ilana
freesurfer@nmr.mgh.harvard.edu
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Douglas Greve -
Ilana Hairston -
Ilana Hairston