help > Same statistic value in all the edges
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Apr 12, 2023  06:04 PM | Mariana Vallejo-Azar
Same statistic value in all the edges
Dear
I ran a patient group vs healthy control group analysis, running a t-test analysis with a contrast of [0,1,0,0,0] and a threshold equivalent to 4. The obtained p-value was 0.037. What I find curious is that all 12 links obtained had the same statistical value of 4.24. I have already verified the data and the combined matrix, and the result persists. Any idea what could be causing this?
I appreciate your help
Attachment: combined.mat
Apr 13, 2023  12:04 PM | Andrew Zalesky
RE: Same statistic value in all the edges
Hi Mariana,

this is technically possible, but it is unlikely for all 12 edges to have the exact same t-stat value.

You may want to manually compute the t-test for a few of these edges to confirm the finding.

Andrew


Originally posted by Mariana Vallejo-Azar:
Dear
I ran a patient group vs healthy control group analysis, running a t-test analysis with a contrast of [0,1,0,0,0] and a threshold equivalent to 4. The obtained p-value was 0.037. What I find curious is that all 12 links obtained had the same statistical value of 4.24. I have already verified the data and the combined matrix, and the result persists. Any idea what could be causing this?
I appreciate your help
Apr 17, 2023  02:04 PM | Mariana Vallejo-Azar
RE: Same statistic value in all the edges
Dear Andrew

I understand. Is there any way to perform t-tests for each individual edge in NBS? Thank you very much
Apr 18, 2023  07:04 AM | Andrew Zalesky
RE: Same statistic value in all the edges
Hi, 

yes - there is an example of a t-test under the Stats help button. 

This will perform a t-test for each edge independently. 
Andrew

Originally posted by Mariana Vallejo-Azar:
Dear Andrew

I understand. Is there any way to perform t-tests for each individual edge in NBS? Thank you very much