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 Chen
July 02, 2009 02:03PM
Jatin,

The conventional approach to testing linear trend with 3 levels, assuming equally spaced, is to assign weights of -1, 0, and 1. If you are concerned that the middle level is not really considered in the test, you can run two extra tests, one with High vs. Medium, and the other with Medium vs. Low. The combination of the 3 tests should be good enough to identify linearity. In the meantime, add a quadratic test with weights of 1, -2, and 1, and see if quadratic relation exists among the 3 levels.

Gang
Reply Quote
RSS
Subject Author Posted

linear effects

Jatin July 01, 2009 11:22PM

Re: linear effects

Gang Chen July 02, 2009 02:03PM

Re: linear effects

Jatin July 02, 2009 02:20PM

Re: linear effects

Gang Chen July 02, 2009 02:25PM