Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: st: Shapes of two Inverted U curves (same model on two different samples)
From
Maarten Buis <[email protected]>
To
[email protected]
Subject
Re: st: Shapes of two Inverted U curves (same model on two different samples)
Date
Mon, 4 Jul 2011 21:28:58 +0200
On Mon, Jul 4, 2011 at 7:12 PM, L.M.A. Mulotte wrote:
> I have an OLS model that includes both a linear effect and the quadratic term. I run this model on two samples, one with a treatment (sample X) and one without treatment (Sample Y). <snip> Is there any means to test whether the "legs" of Curve Y are steeper than the "legs" of Curve X?
The curve with the largest absolute value of the parameter on the
squared term will have the steepest legs, i.e. will be more peaked. So
you can just use -test- to test the hypothesis that the parameters for
the squared term in the treatment sample and the control sample are
the same, which corresponds to the hypothesis that the two curves are
equally steep.
Hope this helps,
Maarten
--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://www.maartenbuis.nl
--------------------------
*
* 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/