A cause other than data based on standardized regression was identified. It is that the manual command added with target <- at the left hand side.
C1 did not work but C2 did. C1 target<-dredge(mig.stds, subset = temp_max) C2 dredge(mig.stds, subset = temp_max) Elaine On Wed, Aug 18, 2010 at 5:37 PM, elaine kuo <elaine.kuo...@gmail.com> wrote: > >> > >> Please suggest how to define subset in my case >> >> How would I know? I still haven't seen your data. You seem to be >> mistaken on what is and is not included in your model and you fitted it. >> What hope do we have...? However, given the model 'mig.stds' from above >> in this email: >> >> > mig.stds <-lm(SummerM_ratio ~ temp_max + evi_mean + topo_var + >> > topo_mean + coast + Iso_index_0808, >> > ## now tell R were to find the variables in formula >> > data = datum.std) >> > ## If you are fitting a Gaussian GLM it is better fitted with lm() >> >> If you want to consider dredged models containing temp_max, then you >> would do >> >> dredge(mig.stds, subset = temp_max) >> >> If you want models that contain temp_max and coast, then you'd do >> >> dredge(mig.stds, subset = temp_max & coast) >> >> or >> >> dredge(mig.stds, fixed = ~ temp_max + coast) >> >> The bits you include in subset or fixed are the names of your variables >> that you want in or out of the models. In your case, the names of the >> variables as input into the model formula. With 'subset' you need to use >> logical operators (and [&], or [|]) whilst with 'fixed' you can specify >> a formula of variables that should be included or excluded in the same >> way you'd write any R formula. >> >> But, now having been told this, please note that this is *all* discussed >> on the ?dredge help page if you bother to read it. I've never used this >> package, and, OK, I have used R for going on for 11 or 12 years now so >> am used to reading help pages and understand the language a bit more you >> perhaps do, but you do seem to be asking questions or running into >> problems that are all covered by the help pages. >> >> => I posted it for help, after following the manual with the command >> dredge but receiving an error message two days ago. >> > > >> command target<-dredge(mig.stds, subset = temp_max) >> > error in eval(expr, envir, enclos) : 'temp_max' not found > > One possible cause could be data = datam.std. > datam.std was produced as the code below, which seemed to make it hard to > find explanatory variables. > Please kindly share your experience in R, because I am unsure if my > assumption is logical or not. > > Also, please kindly advise how to modify the command for dredging subset if > possible. > ( command target<-dredge(mig.stds, subset = temp_max)) > Thank you in advance. > > Elaine > > code > library(MuMIn) > datam <-read.csv("c:/migration/Mig_ratio_20100817.csv",header=T, > row.names=1) > > # std regression model (16 indep. variables) > datam.sd<-scale(datam) > datam.std<-as.data.frame(datam.sd) > summary (datam.std) > mean(datam.std) > > # obtain standard deviation > sd(datam.std) > > mig.stds > <-lm(SummerM_ratio~temp_ran+temp_mean+temp_max+temp_min+evi_ran+evi_mean+evi_max+evi_min+prec_ran+prec_mean+prec_max+prec_min+topo_var+topo_mean+coast+Iso_index_0808,data=datam.std) > > summary(mig.stds) > > > > [[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.