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Thank you! Now I see how permutation works. So given about 100-200 subjects
in the normal group, doing 1000 permutations is of no help.
In fact, in my cortical thickness abnormality test, no matter how many
times of permutations I take, the original
There are actually only N-1 permutations that you can make:
Real matrix:
1 0
0 1
0 1
0 1
0 1
Permutation 1:
0 1
1 0
0 1
0 1
0 1
Permutation 2:
0 1
0 1
1 0
0 1
0 1
On 8/4/2020 10:41 AM, Xiaojiang Yang wrote:
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Hi Doug,
I am still uncertain how to
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Hi Doug,
I am still uncertain how to permutate the data for multiple comparisons.
Please help me with a little more details on this. For example, could you
give me 2-3 examples of the permutations for the matrix you gave to me?
In addition, if you
You would have a design matrix with two columns and rows equal to n+1, eg
1 0
0 1
0 1
0 1
0 1
... n times
you would then permute the design matrix
On 7/23/2020 12:06 PM, Xiaojiang Yang wrote:
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Hi Doug,
For the first question, you answered "It is unusual,
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Hi Doug,
For the first question, you answered "It is unusual, though it should
work". Could you please briefly describe the way FS used to permute (based
on my notation v0, v1, ... vn)? Or, the usual way to permute?
The way I described seems to be
On 7/21/2020 11:45 AM, Xiaojiang Yang wrote:
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Hi Doug,
For your questions:
1. "Not sure what you mean by in the ROI. Are you trying to permute across
space? That generally does not work because the points are not
exchangeable across space."
By "In the
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Hi Doug,
For your questions:
1. "Not sure what you mean by in the ROI. Are you trying to permute
across space? That generally does not work because the points are not
exchangeable across space."
By "In the ROI", I mean for all vertices listed in
On 7/21/2020 1:12 AM, Xiaojiang Yang wrote:
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Dear FS experts,
Instead of using mri_glmfit-sim, I am trying to implement a customized
multiple comparison correction algorithm using permutation. Before I
implement my own, I want to make sure my
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Dear FS experts,
Instead of using mri_glmfit-sim, I am trying to implement a customized
multiple comparison correction algorithm using permutation. Before I
implement my own, I want to make sure my permutation idea is correct. So I
was looking at how
