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  

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July 03, 2021 06:06PM
> Is this the correct way to code for categorical variables of no-interest that have more than two levels in 3dttest++?

It looks fine if you assume there are no interactions among all the explanatory variables.

> is there a significant difference in the interpretation of the results when coding using 1/-1 versus 0.5/-0.5?

The only difference is: with 1/-1 coding, the variable is associated with half of the group difference (i.e., (A - B) / 2) while with 0.5/-0.5 coding, the variable is associated with the group difference (i.e., A - B).

Gang
Subject Author Posted

3dttest++ - coding categorical covariates?

janelleliu July 02, 2021 05:54PM

Re: 3dttest++ - coding categorical covariates?

gang July 03, 2021 06:06PM

Re: 3dttest++ - coding categorical covariates?

janelleliu July 06, 2021 12:31PM

Re: 3dttest++ - coding categorical covariates?

janelleliu July 07, 2021 04:00PM

Re: 3dttest++ - coding categorical covariates?

gang July 08, 2021 07:38PM

Re: 3dttest++ - coding categorical covariates?

janelleliu July 13, 2021 02:52PM

Re: 3dttest++ - coding categorical covariates?

gang July 14, 2021 12:55PM

Re: 3dttest++ - coding categorical covariates?

janelleliu July 14, 2021 01:36PM

Re: 3dttest++ - coding categorical covariates?

gang July 14, 2021 05:16PM

Re: 3dttest++ - coding categorical covariates?

janelleliu July 14, 2021 06:39PM

Re: 3dttest++ - coding categorical covariates?

janelleliu July 23, 2021 04:07PM

Re: 3dttest++ - coding categorical covariates?

janelleliu July 23, 2021 05:28PM

Re: 3dttest++ - coding categorical covariates?

gang July 23, 2021 06:18PM