[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

st: RE: RE: Testing for interaction within linear regression

From   "Nick Cox" <>
To   <>
Subject   st: RE: RE: Testing for interaction within linear regression
Date   Tue, 2 Sep 2008 12:33:01 +0100

All true, but a simpler answer is: -search interaction- (to find out for
yourself) and  -help xi-. 

(Also: please edit emails for previous irrelevant material.) 


Martin Weiss

I do not really know what to make of the normality issue; there is no
requirement on the covariates being normal, AFAIK. If you want to test
validity of your interaction, -generate- the product of the two and add
to your covariates. Then see what kind of an effect (sign, p-value)
out of it. Be warned, though: We had a few posts recently about -nl- and
it is able to see that you used the same covariate twice and adjust the
resulting marginal effect for -mfx- while -regress- would not know that
threw in the covariate itself and some kind of interaction of it with

Apu Chakraborty

I have Stata 9 and wish to test a variable for putative interaction in a
linear regression model where the predictor and dependent variables are
normally distributed. Please could someone let me know how to do this.

*   For searches and help try:

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