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

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gang
February 14, 2017 03:46PM
Phil,

> could you clarify why it's not DOF-3 as was suggested in Daniele's original post?

The conventional formula of converting Pearson correlation to standardized Z-score is (1/2) * ln((1+r)/(1-r)) * sqrt(N-3), where N is the sample size (number of time points in the time series in FMRI data), or (1/2) * ln((1+r)/(1-r)) * sqrt(DOF-2), in which DOF is N-1 for the typical Pearson correlation computation in a regression model with only one regressor (intercept). I just generalized the latter formula to the situation with multiple regressors.

Gang
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Subject Author Posted

Degree of Freedom

mallow February 13, 2017 02:38PM

Re: Degree of Freedom

gang February 14, 2017 08:48AM

Re: Degree of Freedom

Phil Burton February 14, 2017 02:02PM

Re: Degree of Freedom

gang February 14, 2017 03:46PM

Re: Degree of Freedom

mallow February 15, 2017 03:52PM