For noise compare the values in the rstd.mgh file, for effect size look
in the gamma.mgh file

On 07/24/2018 12:27 PM, Martin Juneja wrote:
>
>         External Email - Use Caution
>
> Hi Dr. Greve,
>
> Thanks for your quick reply. Could you please give me more details how
> can I check this whether its because of noise or its because of less
> CV difference?
> I am not sure what method/way is the best and commonly used to confirm
> these factors.
>
> Thanks.
>
> On Tue, Jul 24, 2018 at 7:06 AM, Douglas Greve <dgreve@mgh.harvard.edu

> <mailto:dgreve@mgh.harvard.edu>> wrote:
>
>     your results could have vanished after ICV correction for one of
>     two reasons: the CV difference became less or the values became
>     noisier (or a combination). So check in your data which one of
>     those things happened.
>
>
>     On 7/23/18 8:30 PM, Martin Juneja wrote:
>>
>>             External Email - Use Caution
>>
>>     Hello experts,
>>
>>     I am interested in identifying regions of interest by comparing
>>     cortical volume (CV) between controls and patients.
>>
>>     After including age and sex as my covariates, I identified
>>     regions X1 and X2, which showed significantly lower CV for
>>     patients (as compared to controls).
>>
>>     But after I include ICV as another covariate, my results show
>>     that for none of the areas there is any significant difference in
>>     CV, i.e. my results vanish.
>>
>>     When I checked subjectwise ICV for each group, I found that there
>>     is almost significant difference (two-sampled t-test, p = 0.067)
>>     in ICV between two groups, but interestingly mean group ICV for
>>     patients group was larger compared than mean ICV for controls.
>>     But as I said earlier, regions X1 and X2 had significantly lower
>>     CV for patients (as compared to controls), when I didn't include
>>     ICV as covariate.
>>
>>     Could you please help me in interpreting these results? Is there
>>     any advice regarding inclusion of ICV as covariate? Or my results
>>     are purely because of differences in ICV between groups, and
>>     there is no real findings regarding the regions identified (X1
>>     and X2)?
>>
>>     Thanks a lot !
>>
>>
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