Date:         Sun, 21 Jun 2009 17:29:41 -0400
Reply-To:     Arthur Tabachneck <art297@NETSCAPE.NET>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Arthur Tabachneck <art297@NETSCAPE.NET>
Subject:      Re: Deviance versus log likelihood
Comments: To: b_miner@LIVE.COM

The variable names are different in the two assignments and I'm not sure
what the -2(etc, etc.) mean.

If you're just multiplying the same number by two, I would think that both
the means and variance would simply be doubled as compared to the first
calculation.

Art
--------
On Sun, 21 Jun 2009 12:17:54 -0700, Bminer <b_miner@LIVE.COM> wrote:

>I am used to testing constraints on parameters (two nested models) in
>logistic regression as either:
>
>Deviance_reduced - Deviance_full
>or
>-2(LL_reduced - LL_full). Both give the same value to compare to
>critical values of chi-square.
>
>Using genmod and a normal error, identity link model the two values
>above are not the same. Why?
>
>Which should be used in a likelihood ratio test?
>Thanks!