Hi Liam, 

There is no "right" or "wrong" threshold. 

For the one-sample test, the test statistic is based on mean connectivity (as opposed to a t-statistic), so depending on your connectivity values, you may want to try a relatively low threshold, compared to the t-statistic threshold used for the two-sample t-test. 

In practice, the one-sample test is rarely used. 

Andrew

Originally posted by liam nestor:

  

Dear Andrew

I have came across this discussion and I'm curious about why you are recommending a much lower range of thresholds for a one-sample t-test.

I conducted some one-sample t-test analyses to examine within group patterns of connectivity. 

I have found that using the same t threshold as I have used for unpaired t-test analyses does not yield any significant results.

If I open the NBS.test_stat file generated by the one-sample t-test analysis, the values look like coefficient values, not t-stat values.
 
If I lower the t threshold to just below 1 for the one-sample t-test analyses, I do see significant results.  

Is there something different in the thresholding process for a one-sample t-test compared to an unpaired t-test that I need to consider? Am I getting something wrong here?

All the best , Liam.