Dear Alessio, A few remarks.
- R-sig-mixed models is a better list for this kind of questions - use the glmer() function if you want logistic or poisson regression - the error you are getting is an indication that the model is too complex for the data - watch for colinearity in the covariates Best regards, Thierry > -----Oorspronkelijk bericht----- > Van: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > Namens Alessio Unisi > Verzonden: maandag 21 november 2011 18:20 > Aan: r-help@r-project.org > Onderwerp: [R] errors with lme4 > Urgentie: Hoog > > Dear list, > i'm a new R user, so I apologize if the topic is already being addressed by > some > other user. > > I'm trying to determine if the reproductive success of a species of bird is > related > to a list of covariates. > > These are the covariates: > § elev: elevation of nest (meters) > § seadist: distance from the sea (meters) > § meanterranova: records of temperature > § minpengS1: records of temperature > § wchillpengS1: records of temperature > § minpengS2: records of temperature > § wchillpengS2: records of temperature > § nnd: nearest neighbour distance > § npd: nearest penguin distance > § eggs: numbers of eggs > § lay: laying date (julian calendar) > § hatch: hatching date (julian calendar) > I have some NAs in the data. > > I want to test the model with all the variable then i want to remove some, but > the ideal model: > GLM.1 <-lmer(fledgesucc ~ +lay +hatch +elev +seadist +nnd +npd > +meanterranova +minpengS1 +minpengS2 +wchillpengS1 +wchillpengS2 > +(1|territory), family=binomial(logit), data=fledge) > > doesn't work because of these errors: > 'Warning message: In mer_finalize(ans) : gr cannot be computed at initial par > (65)'. > "matrix is not symmetric [1,2]" > > If i delete one or more of the T records (i.e. minpengS2 +wchillpengS2) the > model works...below and example: > > GLM.16 <-lmer(fledgesucc ~ lay +hatch +elev +seadist +nnd +npd > +meanterranova +minpengS1 +(1|territory), family=binomial(logit), > data=fledge) > > > summary(GLM.16) > Generalized linear mixed model fit by the Laplace approximation > Formula: fledgesucc ~ lay + hatch + elev + seadist + nnd + npd + > meanterranova + minpengS1 + (1 | territory) > Data: fledge > AIC BIC logLik deviance > 174 204.2 -77 154 > Random effects: > Groups Name Variance Std.Dev. > territory (Intercept) 0.54308 0.73694 > Number of obs: 152, groups: territory, 96 > > Fixed effects: > Estimate Std. Error z value Pr(>|z|) > (Intercept) 14.136846 14.510089 0.974 0.330 > lay -0.007642 0.267913 -0.028 0.977 > hatch -0.025947 0.267318 -0.097 0.923 > elev 0.007481 0.027765 0.270 0.788 > seadist -0.004277 0.004550 -0.940 0.347 > nnd -0.035535 0.026504 -1.341 0.180 > npd 0.003788 0.005521 0.686 0.493 > meanterranova 1.242570 1.426158 0.871 0.384 > minpengS1 -0.399852 0.418722 -0.955 0.340 > > Correlation of Fixed Effects: > (Intr) lay hatch elev seadst nnd npd mntrrn > lay 0.411 > hatch -0.515 -0.993 > elev -0.015 0.141 -0.135 > seadist -0.003 -0.023 0.019 -0.440 > nnd -0.061 0.066 -0.059 -0.020 0.231 > npd 0.033 -0.108 0.100 0.298 -0.498 -0.338 > meanterranv 0.459 -0.118 0.075 -0.061 0.014 -0.048 0.130 > minpengS1 -0.540 0.015 0.035 0.032 0.000 0.039 -0.086 -0.970 > > > I've attached an example of my dataset only 15 rows just to see the > dataset. Let me know if you need more informations. > > Thanks in advance for your help and advices! > regards > > -- > Alessio Franceschi > Phd student > Dipartimento di Scienze Ambientali "G. Sarfatti" > Università di Siena > Via P.A. Mattioli, 8 - 53100 Siena (Italy) > Cell. +393384431806 > email: francesc...@unisi.it; alfrances...@alice.it ______________________________________________ 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.
