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
|
John Christie
February 15, 2008 02:41PM
I was studying how to prepare an event related design and went through howto3.

It turns out that the design I want is very similar to that one. Therefore, it was just a matter of changing a few parameters to get what I wanted. As I looked at things more carefully it seemed to me that the whole venture is rather pointless.

Even when I changed the dt in waver to 0.2 the actual variance in norm std. dev. was relatively small. Looking at the worse one I found (10,000 iters) came back with the matrix as "VERY GOOD". It seems like it's very difficult to come up with a bad sequencing in the modelling.

However, in real life, it seems like there are "stories" about how it is very easy to come up with an identity problem in your event related design. So, is it that this modelling isn't very reflective of real life or is the fear of multicollinearity a little unwarranted as long as you randomize and jitter?
Reply Quote
RSS
Subject Author Posted

preparing event related designs

John Christie February 15, 2008 02:41PM

Re: preparing event related designs

Gang Chen February 15, 2008 03:08PM