Date: Fri, 28 Apr 2006 21:15:03 -0400
Reply-To: Richard Ristow <firstname.lastname@example.org>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Richard Ristow <email@example.com>
Subject: Re: R in Linear Regression
Content-Type: text/plain; charset=iso-8859-1; format=flowed;
At 06:24 PM 4/28/2006, Marc Halbrügge wrote:
>>Also, note that R (usually noted by an
>>uppercase r) is the correlation coefficient,
>>has a range of possible values from -1 to +1
>>(indicating from > perfect inverse correlation
>>to perfect direct correlation).
>In linear regression, the correlation between
>observed and predicted values cannot become
>negative. This follows from minimizing the
>squared differences between observed and predicted values.
You're right; it can't. But the correlation
between observed, or predicted, values with
predictOR variables (IVs) can very readily be
negative; and that's what's being discussed.