Re: Sign on regression coef?

Posted by lts1 on Jan 03, 2007; 2:54am
URL: http://spssx-discussion.165.s1.nabble.com/Sign-on-regression-coef-tp1072952p1072959.html

Hi William,

    Thanks for the reply.  I considered supression but the correlation
between the two IVs is .385 (p < .001).  Is that high enough for
suppression?  Also, I thought that a condition of suppression was that the
suppressor variable be uncorrelated with the DV (in my case r = .176, p <
.05).  Is this incorrect?  Thanks in advance.

    Best,
        Lisa


----- Original Message -----
From: "William B. Ware" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, January 02, 2007 9:30 PM
Subject: Re: Sign on regression coef?

> Lisa,
>
> Look at the correlation between the two IVs.  I'm going to guess that it
> is pretty large... I think that what you have is a case of "suppression."
> Check out one of the older editions of Cohen and Cohen or Cohen, Cohen,
> Aiken, and West for an explanation...
>
> wbw
>
> __________________________________________________________________________
> William B. Ware, Professor                         Educational Psychology,
> CB# 3500                                       Measurement, and Evaluation
> University of North Carolina                         PHONE  [phone]
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> __________________________________________________________________________
>
>
> On Tue, 2 Jan 2007, Lisa Stickney wrote:
>
>> Hi SPSSers,
>>
>>    First off, Happy New Year to all.  Next, my apologies for posting a
>> stats question & not an SPSS question, but I'm hoping someone can help
>> me.  I have 3 variables: 2 independent & 1 dependent.  When I look at the
>> correlation table, they all correlate positively with each other.
>> However, when I put them in a regression, the regression coefficient on
>> one of the independent variables becomes negative.  Can anyone tell me
>> when/why this might occur?  Thanks in advance.
>>
>>    Best,
>>        Lisa
>>
>> Lisa T. Stickney
>> Ph.D. Candidate
>> The Fox School of Business
>>     and Management
>> Temple University
>> [hidden email]
>>
>