--- On Tue, 8/12/09, Rahsaan Maxwell wrote:
> My problem is that some of the independent variables have
> non-linear relationships with the DV. Normally, I understood
> that to address this problem one should include the IV plus the
> IV squared. However, my variables are all standardized to mean
> zero so when I square them that obviously turns them into
> garbage.
I am guessing that you are confusing the logarithm with squaring,
there is no problem with adding a squared variable to a model
whose original values (before squaring) were sometimes negative.
Note however that a parabola (the original variable + the variable
squared) is a very special kind of non-linear relationship that
could very well be inappropriate in your case. An attractive
alternative that is more flexible are splines (see: -help mkspline-)
Hope this helps,
Maarten
--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://www.maartenbuis.nl
--------------------------
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