It will not
On 10/13/16 10:34 AM, Eelco van Duinkerken wrote:
Ah sorry for the low level of info. I am aiming to do a simple group
comparison, where I'm comparing thickness between controls and obese
or T2DM patients, regressing out the effect of age, sex and,
hypertension. So I created one t
It will be constrained by the group with the smaller number of subjects.
There is not anything wrong with unequal group sizes, but it is less
efficient than if you had split your acquisitions evenly.
On 10/13/16 10:17 AM, Bruce Fischl wrote:
Hi Eelco
it depends on how you setup your GLM. A
Thank you Jurgen!
That helps a lot. Good to know that the results are not driven by any
difference in varience.
Thanks all,
Eelco
2016-10-13 12:00 GMT-03:00 Juergen Haenggi :
> Dear Eelco
>
> years ago i posed a similar question on the FS email list
>
> https://mail.nmr.mgh.harvard.edu/pipermai
Dear Eelco
years ago i posed a similar question on the FS email list
https://mail.nmr.mgh.harvard.edu/pipermail//freesurfer/2011-November/021386.html
a part of the response is below
>>> The other question is how mri_glmfit estimates the variance. Because I have
>>> only one subject in the patie
Ah sorry for the low level of info. I am aiming to do a simple group
comparison, where I'm comparing thickness between controls and obese or
T2DM patients, regressing out the effect of age, sex and, hypertension. So
I created one thickness file with fwhm 10 containing all participants of
the 3 grou
Thanks for the quick reply!
So if I understand correctly, the power of say the controls vs. diabetes
(indeed it is type 2 diabetes) comparison is constrained by the sample size
of the obese group?
2016-10-13 11:02 GMT-03:00 Bruce Fischl :
> Hi Eelco
>
> it isn't really a question of whether our
Hi Eelco
it depends on how you setup your GLM. Are you trying to regress out the
effects of obesity in some way? If you give us more details I expect
someone else can answer your question (Doug!)
cheers
Bruce
On Thu, 13 Oct 2016, Eelco van Duinkerken
wrote:
Thanks for the quick reply!
S
Hi Eelco
it isn't really a question of whether our implementation is senstitive to
this. It's that in general your power will be constrained by the size of
the smaller group (I assume this is Type 2 diabetes by the way).
cheers
Bruce
On Thu, 13 Oct 2016, Eelco van Duinkerken wrote:
> Hi all,
Hi all,
I am using FS with data from 2 different studies that were acquired on the
same MRI-machine with the same T1 and FLAIR sequences. Unfortunately, the
group sizes are not very balanced, with 31 controls, 16 obese and 32
diabetes patients.
Is the GLM for thickness used in FS very sensitive t
