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From | "Feiveson, Alan H. (JSC-SK311)" <alan.h.feiveson@nasa.gov> |
To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
Subject | RE: st: RE: loglink and normality, mixed model |
Date | Tue, 25 Feb 2014 14:17:01 +0000 |
Hi Ruud - I experimented with some simulated clustered normally distributed data (y) with positive subject-specific means, but large enough error term so that some values of y were negative. -meglm- worked fine. In my simulation, I purposely generated all the subject-specific means to be positive. I think the problem may be that with a log link, all the subject-specific means must be positive, so that if the estimated variance of the random intercept is too large at any stage of the estimation, some subject-specific means would become negative, thus conflicting with the model. Al -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Ruud van Lieshout Sent: Tuesday, February 25, 2014 4:08 AM To: statalist@hsphsun2.harvard.edu Subject: RE: st: RE: loglink and normality, mixed model hi Al, well in theory you are right, but my question also holds for negative values ..The model can generate negative values (eps ~N(0, sigma^2)) but meglm can't handles those !! Why not? regards, Ruud * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/