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st: RE: RE: comparing mean


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: RE: comparing mean
Date   Mon, 9 Aug 2004 17:58:40 +0100

In addition, a -qqplot- is one way of 
looking at the two distributions. There 
are other graphical methods too, but -qqplot- is 
one pretty closely directed at this kind of problem. 

Nick 
n.j.cox@durham.ac.uk 

Yulia Marchenko
 
> 
> On Monday, Samir wrote:
> 
> >Dear Statalisters,
> >I am comparing average change in a utility score of patients in two
> >groups. I see that the initial distribution of utility score is not
> >same, one group have more patients with higher severity than 
> the other.
> >How can I compare the mean between these two groups 
> controlling for the
> >dissimilar distribution? How can I do it in Stata?
> 
> Before deciding what type of test to use you need to look at the
> distribution of scores for each group. If it is fairly 
> "bell-shaped" and
> does not have severe outliers the usual two-sample t-test to 
> compare means
> can be used. Stata has -ttest- command to perform this test. 

... 

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