Re: [R] negative AIC and BIC values in gls
It's fine. Just interpret them as you would any other (lower is better). And it is the printed logLik that is out of step here. log-likelihoods _should_ be negative. That is not quite the case; in models with small variances log-likelihoods can easily become positive, consider eg: dnorm(0,0,0.1,log=T) [1] 1.383647 hth, Ingmar -- David. On 22 August 2012 16:43, Gary Dong pdxgary...@gmail.com wrote: Dear R users, I obtained negative AIC and BIC and positive Loglik values in a gls model. Is this normal? how should I interpret them? Thanks! AIC BIC logLik -659.978 -587.5541 345.989 Best Gary David Winsemius, MD Alameda, CA, USA __** R-help@r-project.org mailing list https://stat.ethz.ch/mailman/**listinfo/r-helphttps://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/** posting-guide.html http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] negative AIC and BIC values in gls
O course! And for the same reason, my stupid comment should be ignored. -- Bert On Thu, Aug 23, 2012 at 12:02 AM, Ingmar Visser i.vis...@uva.nl wrote: It's fine. Just interpret them as you would any other (lower is better). And it is the printed logLik that is out of step here. log-likelihoods _should_ be negative. That is not quite the case; in models with small variances log-likelihoods can easily become positive, consider eg: dnorm(0,0,0.1,log=T) [1] 1.383647 hth, Ingmar -- David. On 22 August 2012 16:43, Gary Dong pdxgary...@gmail.com wrote: Dear R users, I obtained negative AIC and BIC and positive Loglik values in a gls model. Is this normal? how should I interpret them? Thanks! AIC BIC logLik -659.978 -587.5541 345.989 Best Gary David Winsemius, MD Alameda, CA, USA __** R-help@r-project.org mailing list https://stat.ethz.ch/mailman/**listinfo/r-helphttps://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/** posting-guide.html http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] negative AIC and BIC values in gls
On Aug 23, 2012, at 12:02 AM, Ingmar Visser wrote: It's fine. Just interpret them as you would any other (lower is better). And it is the printed logLik that is out of step here. log- likelihoods _should_ be negative. That is not quite the case; in models with small variances log- likelihoods can easily become positive, consider eg: dnorm(0,0,0.1,log=T) [1] 1.383647 We must be using different definitions of likelihood. (I do understand that densities can be greater than one when the domain is restricted.) -- David. hth, Ingmar -- David. On 22 August 2012 16:43, Gary Dong pdxgary...@gmail.com wrote: Dear R users, I obtained negative AIC and BIC and positive Loglik values in a gls model. Is this normal? how should I interpret them? Thanks! AIC BIC logLik -659.978 -587.5541 345.989 Best Gary David Winsemius, MD Alameda, CA, USA __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. David Winsemius, MD Alameda, CA, USA [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] negative AIC and BIC values in gls
Dear R users, I obtained negative AIC and BIC and positive Loglik values in a gls model. Is this normal? how should I interpret them? Thanks! AIC BIC logLik -659.978 -587.5541 345.989 Best Gary [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] negative AIC and BIC values in gls
It's fine. Just interpret them as you would any other (lower is better). On 22 August 2012 16:43, Gary Dong pdxgary...@gmail.com wrote: Dear R users, I obtained negative AIC and BIC and positive Loglik values in a gls model. Is this normal? how should I interpret them? Thanks! AIC BIC logLik -659.978 -587.5541 345.989 Best Gary [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] negative AIC and BIC values in gls
On Aug 22, 2012, at 5:17 PM, Jeremy Miles wrote: It's fine. Just interpret them as you would any other (lower is better). And it is the printed logLik that is out of step here. log-likelihoods _should_ be negative. -- David. On 22 August 2012 16:43, Gary Dong pdxgary...@gmail.com wrote: Dear R users, I obtained negative AIC and BIC and positive Loglik values in a gls model. Is this normal? how should I interpret them? Thanks! AIC BIC logLik -659.978 -587.5541 345.989 Best Gary David Winsemius, MD Alameda, CA, USA __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] negative AIC and BIC values in gls
Inline.
On Wed, Aug 22, 2012 at 5:17 PM, Jeremy Miles jeremy.mi...@gmail.com wrote:
It's fine. Just interpret them as you would any other (lower is better).
I don't think so. I believe all 3 values are the negative of what they
should be. AIC is defined as -2*log(L) + k*{degrees of freedom for
model) . BIC is similar (different k's). This should be positive and,
as you said, the smaller the better. So if the signs are reversed,
models with lower absolute AIC and BIC -- bigger negative AIC and BIC
-- is what you want.
However, this really needs comment by an expert, which I ain't. I also
suggest you post to r-sig-mixed-models, since gls is an nlme function.
Cheers,
Bert
On 22 August 2012 16:43, Gary Dong pdxgary...@gmail.com wrote:
Dear R users,
I obtained negative AIC and BIC and positive Loglik values in a gls model.
Is this normal? how should I interpret them? Thanks!
AIC BIC logLik
-659.978 -587.5541 345.989
Best
Gary
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
