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Thanks for your detail information. I will try it now.
Ting
> On Jul 16, 2018, at 1:26 PM, Douglas N. Greve <dgr...@mgh.harvard.edu> wrote:
>
> It is different than the MC simulations. When you run mri_glmfit,
> specify the --save-yhat option. This will create a file called yhat.mgh
> which will be used as the non-null basis of the simulation. You will
> have to add noise to this file and analyze through mri_glmfit and
> mri_glmfi-sim and see if you get your cluster. Do this many times
> (~1000) with different noise each time, then simply compute how often
> you see your cluster (this is the true positive rate). You can add the
> noise in matlab, something like
>
> yhat = MRIread('yhat.mgh');
> rstd = MRIread('rstd.mgh'); % standard deviation
> for n = 1:1000
> y = yhat;
> y.vol = yhat.vol + randn(size(rstd.vol)).*rstd.vol; % add noise
> fname = sprintf('synth%04d.mgh',n);
> MRIwrite(y,fname);
> end
>
> On 07/16/2018 01:43 PM, Ting Li wrote:
>> External Email - Use Caution
>>
>> Hi Douglas,
>>
>> Thanks for your response. I did the monte carlo simulation. Could you give
>> me any instructions about how to perform a simulation under non-null
>> conditions? Thanks a lot!
>>
>> Best,
>> Ting
>>> On Jul 16, 2018, at 12:15 PM, Douglas N. Greve <dgr...@mgh.harvard.edu>
>>> wrote:
>>>
>>> I'm not sure what you mean by this. power with clusterwise corrections
>>> is quite tricky. You'd have to do a simulation under non-null conditions
>>> to see what the true positive rate is
>>>
>>>
>>>
>>> On 07/10/2018 11:53 AM, Ting Li wrote:
>>>> External Email - Use Caution
>>>>
>>>> Hi Freesurfer Expert,
>>>>
>>>> How can I know the power of my GLM test after I did the clusterwise
>>>> correction? I got this question because I had a problem like this. I have
>>>> 21 subjects for group A and B. Once I delete one subject from group A, one
>>>> of the clusterwise correction results has disappeared. Can you help me on
>>>> this? Thanks a lot!
>>>>
>>>> Best wishes,
>>>> Ting Li
>>>>
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