Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down on April 23, and its replacement, is already up and running.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: ST: postestimation test

From   Maarten buis <>
Subject   Re: st: ST: postestimation test
Date   Fri, 6 Aug 2010 15:17:11 +0000 (GMT)

--- On Fri, 6/8/10, Bontempo, Daniel E wrote:
> The model showed the interaction of two factors was
> significant, and I thought I could use "test" to probe
> which pairs of means were actually different. But some
> comparisons involving the reference condition do not
> work, and I am not sure why the test is giving chisq.
> -----
> . margins condition#ageGrp
> . test 0.condition#1.ageGrp=1.condition#1.ageGrp

this test refers to the parameters in your model, not
to the table you get from margins. To test the differences
in predicted outcomes, you must first specify the -post- 
option in -margins-. 

-test- gives you a Chi square statistic  because it
produces a Wald test of possibly multiple constraints, in
which case it cannot use the normal distribution as the 
sampling distribution of the test statistic.

Hope this helps,

Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen


*   For searches and help try:

© Copyright 1996–2015 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index