Date:         Mon, 13 Apr 1998 17:00:46 +0300
Reply-To:     Amir Hetsroni <amir_h@BARLEY.CTEH.AC.IL>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@UGA.CC.UGA.EDU>
From:         Amir Hetsroni <amir_h@BARLEY.CTEH.AC.IL>
Organization: The Hebrew University of Jerusalem
Subject:      problem with nonlinear regression
Comments: To: "Nichols, David" <nichols@SPSS.COM>
Content-Type: multipart/alternative;

I am working on a database that investigates complex relationship
between interest in an object and the inclination to participate in
activities in favor of the object.
 
Based on the "principal components of attitude" theory by Guttman I
expected to find a W shape relationship between the interest component
and the activities component.
It appears that at least as far as it concerns the object of national
history - mission accomplished (see the control chart below).
 
 However, when it comes to calculating a regression function I am having
a problem. Clearly, the most accurate function is not linear, looks more
like to parabolas, but how do I write this function? What value should
the parameter(s?) have?
I tried to draw a scatter plot to learn more about the function but it
appears that when the sample is large even fairly large linear
relationship (r>0.6), not to mention this case, look messy on a scatter
plot.
Can someone give a hand with the estimation of the function or at least
hint?
 
thanks,
Amir
 
AMIR HETSRONI
 
The Department of Communication
The Hebrew University of Jerusalem
 
E-Mail: msamir@mscc.huji.ac.il
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