Re: <POSSIBLE SPAM>st: RE: RE: comparing different means using ttest

[Steven Samuels <sjsamuels@gmail.com>]

But. Eric, I don't think that pooling will solve the dependence issues  
that Nick mentioned.


Steve

sjsamuels@gmail.com


On Dec 16, 2010, at 1:26 PM, DE SOUZA Eric wrote:

Reply to original post, which once again I have deleted !

Why not just pool your data and regress %GDP-growth on a dummy  
(binary) variable (and a constant, of course) which takes the value of  
one for one of the two sub-samples and zero for the other; and test  
whether the coefficient on the dummy is significantly different from  
zero (or examine its confidence interval) ?
You can robustify for heteroscedasticity.


Eric de Souza
College of Europe
Dyver 11
BE-8000 Brugge (Bruges)
Belgium

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu 
] On Behalf Of Nick Cox
Sent: 16 December 2010 19:17
To: 'statalist@hsphsun2.harvard.edu'
Subject: <POSSIBLE SPAM>st: RE: RE: comparing different means using  
ttest

A senior Stata user, who might not want to be named, pointed out the  
counter-example of a Poisson variable. Clearly correct: if you know  
that your variable is Poisson, then the mean is also the variance.

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

Nick Cox

[...]
any more than the mean of anything tells you about its variability.
[...]


*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/