[R-sig-eco] Poisson regression
Dear all to find relation between non-normal response with independents variable i use this code: model1-gam(Clupeidae~s(depth)+s(temperature)+s(salinity),poisson) the result shown is: There were 50 or more warnings (use warnings() to see the first 50) warnings(model1) Warning messages: 1: In dpois(y, mu, log = TRUE) : non-integer x = 2.079542 Error in cat(list(...), file, sep, fill, labels, append) : argument 2 (type 'list') cannot be handled by 'cat' what is meaning it? do i allow use it for continue? thanks -- Mahnaz [[alternative HTML version deleted]] ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
Re: [R-sig-eco] Poisson regression
On Thu, 2012-05-24 at 11:41 +0430, Mahnaz Rabbaniha wrote: Dear all to find relation between non-normal response with independents variable i use this code: model1-gam(Clupeidae~s(depth)+s(temperature)+s(salinity),poisson) I don't know if this is the problem or not, but you can't call the model that way. if you don't name arguments then you must list them in the order the function expects. You don;t say which `gam()` you use but assuming it is `mgcv:::gam()` then the second argument is `data` and you passed it a function `poisson`. Does it work if you do: model1-gam(Clupeidae~s(depth)+s(temperature)+s(salinity), family = poisson) ? Really though you should be passing it both a data and a family argument. Assuming your data are in object named `mydata` then: model1-gam(Clupeidae~s(depth)+s(temperature)+s(salinity), data = mydata, family = poisson) would be the correct way to work with the function. G the result shown is: There were 50 or more warnings (use warnings() to see the first 50) warnings(model1) Warning messages: 1: In dpois(y, mu, log = TRUE) : non-integer x = 2.079542 Error in cat(list(...), file, sep, fill, labels, append) : argument 2 (type 'list') cannot be handled by 'cat' what is meaning it? do i allow use it for continue? thanks -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Dr. Gavin Simpson [t] +44 (0)20 7679 0522 ECRC, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
Re: [R-sig-eco] Poisson regression
-- Message: 2 Date: Thu, 24 May 2012 11:41:06 +0430 From: Mahnaz Rabbaniharab.mah...@gmail.com To: r-sig-ecologyr-sig-ecology@r-project.org Subject: [R-sig-eco] Poisson regression Message-ID: canlcanxsf0zpyc-r22f32veeeyjq7kfn8ksgkxffc44uty_...@mail.gmail.com Content-Type: text/plain Dear all to find relation between non-normal response with independents variable i use this code: model1-gam(Clupeidae~s(depth)+s(temperature)+s(salinity),poisson) the result shown is: There were 50 or more warnings (use warnings() to see the first 50) warnings(model1) Warning messages: 1: In dpois(y, mu, log = TRUE) : non-integer x = 2.079542 Error in cat(list(...), file, sep, fill, labels, append) : argument 2 (type 'list') cannot be handled by 'cat' what is meaning it? do i allow use it for continue? Check whether your Clupeidae variable contains non-integers... Alain thanks -- Dr. Alain F. Zuur First author of: 1. Analysing Ecological Data (2007). Zuur, AF, Ieno, EN and Smith, GM. Springer. 680 p. URL: www.springer.com/0-387-45967-7 2. Mixed effects models and extensions in ecology with R. (2009). Zuur, AF, Ieno, EN, Walker, N, Saveliev, AA, and Smith, GM. Springer. http://www.springer.com/life+sci/ecology/book/978-0-387-87457-9 3. A Beginner's Guide to R (2009). Zuur, AF, Ieno, EN, Meesters, EHWG. Springer http://www.springer.com/statistics/computational/book/978-0-387-93836-3 4. Zero Inflated Models and Generalized Linear Mixed Models with R. (2012) Zuur, Saveliev, Ieno. http://www.highstat.com/book4.htm Other books: http://www.highstat.com/books.htm Statistical consultancy, courses, data analysis and software Highland Statistics Ltd. 6 Laverock road UK - AB41 6FN Newburgh Tel: 0044 1358 788177 Email: highs...@highstat.com URL: www.highstat.com URL: www.brodgar.com ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
[R-sig-eco] Multiple comparisons among predictors generated from same data
Hello, I'm planning on using a regression model to describe seed set of plants (my response) using some sort of predictor based on temperature. I have a number of temperature variables calculated from the same set of data (hourly temperatures for the growing season, converted to variables such as average temperature, maximum temperature, minimum temperature, degree-days above zero Celsius, degree days above ten Celsius, etc...), and I want to decide which one should be included in my model. I know that I would ideally select one based on prior knowledge of the system (e.g. so-called planned comparisons or choosing a temperature threshold that is known to be important for the development of seeds), but not much is known about this system. I've been warned against testing the significance of multiple predictors using p-values, unless I use Bonferroni correction (or some equivalent). Unfortunately, using Bonferroni correction would result in something like p = 0.05/7 (for seven different temperature variables); a rather small value for detecting anything! I was wondering whether it would be appropriate to instead use likelihood-based techniques (direct comparisons of log-likelihoods or AIC scores) to compare a series of models using each of the alternative predictors in turn, and choose the most relevant temperature variable (i.e. predictor) based on that. Thoughts on the validity of this approach? Would any adjustments have to be made for multiple comparisons if I used this strategy? Jason Straka University of Victoria [[alternative HTML version deleted]] ___ R-sig-ecology mailing list R-sig-ecology@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
