[R] p_values for GLMM
Dear R-users, I was wondering if anybody knows if it's possible to obtain a p value for the full model of a GLMM with the lme4 package. I was told that I should check whether the full model including all the predictor variables is significant before doing stepwise regression or further analysis, but I can't figure out how to do this. I also wanted to know if there's a way of obtaining residuals or predicted values for the same analysis. Thank you very much. Cheers, Cristina. __ R-help@stat.math.ethz.ch 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] p values in lme4 package
Dear R-users, I was wondering if anybody knows if it's possible to obtain a p value for the full model of a GLMM with the lme4 package. I was told that I should check whether the full model including all the predictor variables is significant before doing stepwise regression or further analysis, but I can't figure out how to do this. I also wanted to know if there's a way of obtaining residuals or predicted values for the same analysis. Thank you very much. Cheers, Cristina. __ R-help@stat.math.ethz.ch 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] p-values for GLMMs
Hi there, I have a question about the GLMM that I'm doing, that a statistician friend suggested I should have for my analysis. I would like to know if there's any way of obtaining a p value and R square for the full model (and not each variable separately) as to asses whether this model is somewhat appropriate or not. Can one do this for a GLMM in the lme4 package? The other thing I wanted to know if there's a way to obtain residuals for a GLMM in the lme4 package. I would like to see the effect of the significant variables by plotting the residuals of the model without the variable of interest against the variable of interest, but I haven't found a way of obtaining residuals. I hope somebody can help me with this. Thanks a lot, Cheers, Cristina. __ R-help@stat.math.ethz.ch 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] GLMM plots
Hi R-users, I would like to plot the effects of one of the predictor variables on the response variable in the GLMM I ran with the lme4 package. Usually when doing a multivariate analysis I would obtain the residuals of the model without the predictor variable of interest (x1) and then plot these residuals against X1. But in the lme4 package one can not obtain residuals. Is there any way of obtaining plots of this sort? or any other recommendation somebody could give me regarding this topic? Thanks a lot in advance. Cheers, Cristina. __ R-help@stat.math.ethz.ch 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] Appropriate error distribution
Hi, My name is Cristina. I'm interested in studying which continuos predictor variables (such as grooming received, rank, etc.) affect grooming given, as well a continuos variable. I'm having problems finding an appropriate family distribution to fit the GLMM I'm doing. The response variable, grooming given, has many zeros which does not allow me to use a gamma distribution. I tried with a poisson but since I had to convert the data to integers I fear loosing a lot of information (and anyway my data is originally continuos and not counts). I found in the help archive that someone with a similar problem (continuos data and many zeros) was adviced to use Tweedie models. I don't know anything about this and wouldn't kow if this is appropriate in my case and possible to apply to generalized linear mixed models. I'm wondering if anybody could provide me with any good insights on what distribution I could us and if, in the case of tweedie being a good option, if it can be used with GLMM's.. Thanks a lot, Cristina. __ R-help@stat.math.ethz.ch 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] dispersion_parameter_GLMM's
Hi all, I was wondering if somebody could give me advice regarding the dispersion parameter in GLMM's. I'm a beginner in R and basically in GLMM's. I've ran a GLMM with a poisson family and got really nice results that conform with theory, as well with results that I've obtained previously with other analysis and that others have obtained in similar studies. But the dispersion parameter is too large (25 compared to 1). So I ran a quasipoisson that allows for overdispersion and all of the significant results fell out. My question is, how much does overdispersion invalidate ones results when using a poisson family? What could the reason be for having non significant results with a quasipoisson distribution? If anybody could give me some help with this or/and recommend me literature that is somewhat comprehensible to lay people (i.e. non statisticians) that would be great. Thanks in advance, Cristina. __ R-help@stat.math.ethz.ch 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] residuals in lme4 package
Hi, I have not been able to calculate residuals in the lme4 package. I've been trying the resid() function after I ran a GLMM with the lmer() function, but I get an error message that says residuals are not inserted yet. I looked it up in the help history and I realized that several people have had this problem in the past, related to some bug in this function and fixed it usually just by upgrading the lme4 package or Matrix package. I did, but it didn't work. Does anybody have any idea whats going on? Or could you suggest me another way of getting and plotting the residuals? Thanks a lot, Cristina. -- Cristina Gomes Parisca Max Planck Institute for Evolutionary Anthropology Primatology Deutscher Platz 6 D-04103 Leipzig, Germany Phone: +49 341 3550 220 Fax: +49 341 3550 299 E-mail: [EMAIL PROTECTED] __ R-help@stat.math.ethz.ch 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.
