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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ptaylor
May 24, 2018 06:48PM
A discussion of how and when to use two-sided and one-sided tests:
[www.biorxiv.org]
These are some pretty fundamental aspects of statistical tests. Please read and spread!

A few highlights: 
"Here, we first aim to clarify between cases where one-sided or two-sided testing is appropriate. The general rule can actually
be stated succinctly: If the investigator can justify focusing on one side (direction) based on prior knowledge, then they should
explicitly state their reasoning and decision, and perform their individual one-sided test; otherwise, two-sided testing should be
conducted.  This can be applied straightforwardly to voxelwise, ROI-based or other study approaches, as described below."
"...performing a pair of one-sided tests at the significance level of A is equivalent to performing two-sided testing at the
significance level of 2A, and therefore the expected FPR is actually twice the stated rate."
"This sidedness issue is not a matter of interpretation about effect directionality but simply a black-and-white, quantitative
fact about FPR controllability."

Oh, and there's some code posted online in association with this draft that demonstrates AFNI tools for group analysis + clustering, including the new 3dClusterize (which replaces the older 3dclust in a hopefully more syntactically friendly way). But ya gotta read the whoooole article to find it!

--pt



Edited 3 time(s). Last edit at 05/24/2018 06:57PM by ptaylor.
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Subject Author Posted

A new discussion of important statistical practice

ptaylor May 24, 2018 06:48PM

Re: A new discussion of important statistical practice

Daniel Glen October 02, 2018 02:01PM