AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

History of AFNI updates  

Previous Message Next Message
Message List New Topic Print View
|
gang
February 03, 2022 12:39PM
Try this:

1) Find the degrees of freedom for the t-stat sub-brick using a command like this (assuming the sub-brick number is 9):

3dAttribute BRICK_STATAUX myFile+tlrc'[9]'

The last number is the degrees of freedom.

2) Compute the critical value corresponding to the p-value of, for example, 0.05 (DF is the degrees of freedom from 1) above):

cdf -p2t fitt 0.05 DF

3) Find out the upper bound of 95% uncertainty interval (assuming the critical value from 2) is CR and the beta and t-stat sub-bricks are 8 and 9):

3dcalc -a myFile+tlrc'[8]' -b myFile+tlrc'[9]' -expr 'a+CR*a/b' -prefix upper

and lower bound

3dcalc -a myFile+tlrc'[8]' -b myFile+tlrc'[9]' -expr 'a-CR*a/b' -prefix lower

Gang



Edited 1 time(s). Last edit at 02/03/2022 04:42PM by Gang.
Reply Quote
RSS
Subject Author Posted

confidence interval of betas in single subject

swallowwly February 02, 2022 05:51PM

Re: confidence interval of betas in single subject

gang February 03, 2022 12:39PM

Re: confidence interval of betas in single subject

swallowwly February 03, 2022 02:57PM