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RE: st: Post estimation power estimations.
From
Cameron McIntosh <[email protected]>
To
STATA LIST <[email protected]>
Subject
RE: st: Post estimation power estimations.
Date
Sat, 15 Oct 2011 12:37:21 -0400
What's the correlation between var1 and var2?
Cam
> From: [email protected]
> To: [email protected]
> Date: Sat, 15 Oct 2011 17:45:55 +0200
> Subject: st: Post estimation power estimations.
>
> Evnin' list.
>
> I have a question for you: when you do a ttest and you have no significant difference, you can estimate the group size needed for the between group differences to be significant, using SD and the differences in mean. I know this is a statistical no no - but lets save that discussion for another chain of emails.
>
> My problem is that the between group difference is significant. When i correct for a variable, that shouldent interfere the between group difference dissaperes.
>
> What i've done:
> Xi: regress var1 var2 i.group
> _group_2 p=0.45
> Indicating that the Var2 adjusted var1 between group difference is no longer significant. I believe This is a power issue.
>
> Can i aply the same logic as in ttest exemple, and if so - how to do that in Stata?
>
> Mvh
> Lars Folkestad
>
>
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