Re: [Freesurfer] Power analysis for Qdec

The matlab code is here:

$FREESURFER_HOME/fsfast/toolbox/fast_glmpower.m

There's not much documentation on it. Have you done power analyses before?

doug

On 10/29/2013 10:29 AM, amirhossein manzouri wrote:

Thanks Doug, Would you please provide me the MATLAB code and instruction! BR

On Tue, Oct 29, 2013 at 3:25 PM, Douglas N Greve <greve@nmr.mgh.harvard.edu mailto:greve@nmr.mgh.harvard.edu> wrote:

We don't have a way to do a power analysis directly from QDEC. I
have some matlab code that does it for univariate analysis.

In the QDEC output folder, you will see a glm folder. In that
there will be folders for each contrast. In the contrast folder,
you will see an F.mgh file which will be the F-values. You can
convert this to a t = sign(gamma.mgh)*sqrt(F)

doug



On 10/28/2013 07:27 AM, amirhossein manzouri wrote:

    Hi
    Would you please let me know if it is possible to calculate
    the power for a group comparison in cortical thickness? Also,
    a referee is requesting F-values and T map , are they
    generated by q-dec?
    That would be great if I can get an answer in more detail
    since I have seen the post in FAQ, just need more information
    in detail regarding calculating the power !
    -- 
    Best regards,
    Amirhossein Manzouri



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-- Best regards, Amirhossein Manzouri