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Re: st: ttest
From
Nick Cox <[email protected]>
To
"[email protected]" <[email protected]>
Subject
Re: st: ttest
Date
Fri, 23 Aug 2013 16:54:42 +0100
No; the t-test is a rifle, not a shotgun.
You could do something like this
foreach pair in "1, 2" "1, 3" "1, 4" "2, 3" "2, 4" "3, 4" {
di "pair `pair'"
ttest math_score if inlist(group, `pair'), by(group)
}
But the major statistical point is that the t-test is mis-applied like
this, or so many would argue. Better to use analysis of variance,
followed by whatever post hoc tests you can justify. That means
-anova- or -oneway-.
Nick
[email protected]
On 23 August 2013 16:47, Seok-Woo Kwon <[email protected]> wrote:
> Hello,
>
> I want to performs t-tests for four groups (group1 vs. group2, group 2
> vs. group3, etc). When I tried "ttest math_score, by(group)", it
> gives an error message: "more than 2 groups found, only 2 allowed."
>
> Is there a way to do this without writing command for each comparison?
>
> Thanks.
>
> Seok-Woo Kwon
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