Statalist


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

st: interaction between two continuous variables


From   "alessia matano" <alexis.rtd@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   st: interaction between two continuous variables
Date   Tue, 4 Sep 2007 18:33:27 +0200

Hi,

I am trying to perform a regression trying to put an interaction term
between two continuous variables.
In a first attempt I discretize one of them and then multiply the
relative dummy with the other variable, and I obtained some
interesting effect.
Then I red that this is not correct to be done and it is also
arbitrary (because I decide how descretize one variable...I was
calcultaing some threshold using the percentiles say p(33) p(66))
getting three values.

Therefore I red some papers saying that you should centered the
continuous variables (becuase of problem of multicollinearity: is that
correct?) and then simply multiply them. In this way results are not
so interesting anymore. The main and interacted variables together are
never significant and it happens (and here I would like your help)
that in one case only the interacted is significant while the main
effect is not. Whta does it mean?
Can someone help me.

Thanks
alessia
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index