Re: [R] What error distribution should I use?
Thank's a lot for your help Ben. I already posted my question on r-sig-mixed-models! However you already answered what I needed to know. 2012/3/27 Ben Bolker bbol...@gmail.com Lívia Dorneles Audino livia.audino at gmail.com writes: I'm trying to make a glmm to identify the relationship between insect species richness with fragment size, isolation and time (different years). I already tried to analyse it using poisson distribution error, but I always face with the following warning: *glm.fit: fitted probabilities numerically 0 or 1 occurred * This is probably hapenning because my dataset has a lot of zeros. So, what error distribution should I use? I know you haven't gotten a lot of help on r-sig-mixed-models (sorry), but it would probably be better to post this question there. The answer is that this is a warning, not an error, so it indicates a need for caution but not necessarily that anything is wrong. In this case, an internal call to glm.fit() has difficulty when it tries to fit a subset of that data that are all-zero or all-one. It's quite possibly OK, provided that you've looked at your results, plotted predicted values, etc., and everything seems to make sense. __ 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. -- *Lívia Dorneles Audino* Doutoranda em Entomologia Laboratório de Ecologia e Conservação de Invertebrados Universidade Federal de Lavras [[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] What error distribution should I use?
Thank's for your help Peter! This post is really very informative. It helped a lot! 2012/3/27 Peter Ehlers ehl...@ucalgary.ca On 2012-03-27 15:11, Ben Bolker wrote: Lívia Dorneles Audinolivia.audinoat gmail.com writes: I'm trying to make a glmm to identify the relationship between insect species richness with fragment size, isolation and time (different years). I already tried to analyse it using poisson distribution error, but I always face with the following warning: *glm.fit: fitted probabilities numerically 0 or 1 occurred * This is probably hapenning because my dataset has a lot of zeros. So, what error distribution should I use? I know you haven't gotten a lot of help on r-sig-mixed-models (sorry), but it would probably be better to post this question there. The answer is that this is a warning, not an error, so it indicates a need for caution but not necessarily that anything is wrong. In this case, an internal call to glm.fit() has difficulty when it tries to fit a subset of that data that are all-zero or all-one. It's quite possibly OK, provided that you've looked at your results, plotted predicted values, etc., and everything seems to make sense. Livia: You might also find this quite extensive recent post from Ted Harding informative: https://stat.ethz.ch/**pipermail/r-help/2012-March/**307352.htmlhttps://stat.ethz.ch/pipermail/r-help/2012-March/307352.html Peter Ehlers __** 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. -- *Lívia Dorneles Audino* Doutoranda em Entomologia Laboratório de Ecologia e Conservação de Invertebrados Universidade Federal de Lavras [[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] What error distribution should I use?
Hi Chuck! Actually my data has a lot of zeros because I counted the number of species that is exclusive to each studied fragment. So, my response variable is the number of exclusive species. That's why it has a lot of zeros. I have fragments that do not present exclusive species. Thank's for your help! 2012/3/27 chuck.01 charliethebrow...@gmail.com Could you please post a small example of your data and code which gives you this error. Your assumed error distribution sounds reasonable. I am interested as to why you have zeros... you have sites with species richness ==0 ?? Lívia Dorneles Audino wrote I'm trying to make a glmm to identify the relationship between insect species richness with fragment size, isolation and time (different years). I already tried to analyse it using poisson distribution error, but I always face with the following warning: *glm.fit: fitted probabilities numerically 0 or 1 occurred * This is probably hapenning because my dataset has a lot of zeros. So, what error distribution should I use? -- *Lívia * [[alternative HTML version deleted]] __ R-help@ 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. -- View this message in context: http://r.789695.n4.nabble.com/What-error-distribution-should-I-use-tp4509479p4510351.html Sent from the R help mailing list archive at Nabble.com. __ 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. -- *Lívia Dorneles Audino* Doutoranda em Entomologia Laboratório de Ecologia e Conservação de Invertebrados Universidade Federal de Lavras [[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] What error distribution should I use?
I'm trying to make a glmm to identify the relationship between insect species richness with fragment size, isolation and time (different years). I already tried to analyse it using poisson distribution error, but I always face with the following warning: *glm.fit: fitted probabilities numerically 0 or 1 occurred * This is probably hapenning because my dataset has a lot of zeros. So, what error distribution should I use? -- *Lívia * [[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] What error distribution should I use?
Lívia Dorneles Audino livia.audino at gmail.com writes: I'm trying to make a glmm to identify the relationship between insect species richness with fragment size, isolation and time (different years). I already tried to analyse it using poisson distribution error, but I always face with the following warning: *glm.fit: fitted probabilities numerically 0 or 1 occurred * This is probably hapenning because my dataset has a lot of zeros. So, what error distribution should I use? I know you haven't gotten a lot of help on r-sig-mixed-models (sorry), but it would probably be better to post this question there. The answer is that this is a warning, not an error, so it indicates a need for caution but not necessarily that anything is wrong. In this case, an internal call to glm.fit() has difficulty when it tries to fit a subset of that data that are all-zero or all-one. It's quite possibly OK, provided that you've looked at your results, plotted predicted values, etc., and everything seems to make sense. __ 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] What error distribution should I use?
On 2012-03-27 15:11, Ben Bolker wrote: Lívia Dorneles Audinolivia.audinoat gmail.com writes: I'm trying to make a glmm to identify the relationship between insect species richness with fragment size, isolation and time (different years). I already tried to analyse it using poisson distribution error, but I always face with the following warning: *glm.fit: fitted probabilities numerically 0 or 1 occurred * This is probably hapenning because my dataset has a lot of zeros. So, what error distribution should I use? I know you haven't gotten a lot of help on r-sig-mixed-models (sorry), but it would probably be better to post this question there. The answer is that this is a warning, not an error, so it indicates a need for caution but not necessarily that anything is wrong. In this case, an internal call to glm.fit() has difficulty when it tries to fit a subset of that data that are all-zero or all-one. It's quite possibly OK, provided that you've looked at your results, plotted predicted values, etc., and everything seems to make sense. Livia: You might also find this quite extensive recent post from Ted Harding informative: https://stat.ethz.ch/pipermail/r-help/2012-March/307352.html Peter Ehlers __ 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] What error distribution should I use?
Could you please post a small example of your data and code which gives you this error. Your assumed error distribution sounds reasonable. I am interested as to why you have zeros... you have sites with species richness ==0 ?? Lívia Dorneles Audino wrote I'm trying to make a glmm to identify the relationship between insect species richness with fragment size, isolation and time (different years). I already tried to analyse it using poisson distribution error, but I always face with the following warning: *glm.fit: fitted probabilities numerically 0 or 1 occurred * This is probably hapenning because my dataset has a lot of zeros. So, what error distribution should I use? -- *Lívia * [[alternative HTML version deleted]] __ R-help@ 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. -- View this message in context: http://r.789695.n4.nabble.com/What-error-distribution-should-I-use-tp4509479p4510351.html Sent from the R help mailing list archive at Nabble.com. __ 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.
