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
October 08, 2012 05:34PM
> 1) How should I use homoskedasticity or heteroskedasticity,
> is heteroskedasticity the default type in 3dMEMA?

You found a bug in example 3 of the 3dMEMA help! The option -equal_variance (homoskedasticity) is the default, while option -unequal_variance corresponds to heteroskedasticity.

> 2) I read some response from Gang Chen "I tend to use
> -model_outliers and -unequal_variance (if possible) all the time",
> here, should I use these commands for my analyses?:
>
> -model_outliers \
> -residual_Z \
> -unequal_variance

Try out two analyses, one with -unequal_variance, and the other without, and then see how they compare to each other. Usually they should not differ much.

Gang
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Subject Author Posted

3dMEMA heteroskedasticity or homoskedasticity?

Kai October 08, 2012 03:32PM

Re: 3dMEMA heteroskedasticity or homoskedasticity?

gang October 08, 2012 05:34PM

Re: 3dMEMA heteroskedasticity or homoskedasticity?

Kai October 08, 2012 05:38PM