hello, my data-collection is not yet finished, but i though have started investigating possible analysis methods.
below i give a very close simulation of my future data-set, however there might be more nominal explanatory variables - there will be no continous at all (maybe some ordered nominal..). i tried several packages today, but the one i fancied most was ctree of the party package. i can't see why the given no. of datapoints (n=100) might pose a problem here - but please teach me better, as i might be naive.. i'd be very glad about comments on the use of ctree on suchalike dataset and if i oversee possible pitfalls.... thank you all, kay ###################################################################################### # an example with 3 nominal explanatory variables: # Y is presence of a certain invasive plant species # introduced effect for fac1 and fac3, fac2 without effect. # presence with prob. 0.75 in factor combination fac1=I (say fac1 is geogr. region) and # fac3 = a|b|c (say all richer substrates). # presence is not influenced by fac2, which might be vegetation type, i.e. ###################################################################################### library(party) dat<-cbind( expand.grid(fac1=c("I","II"), fac2=LETTERS[1:5], fac3=letters[1:10])) print(dat<-dat[order(dat$fac1,dat$fac2,dat$fac3),]) dat$fac13<-paste(dat$fac1,dat$fac3,sep="") for(i in 1:nrow(dat)){ ifelse(dat$fac13[i]=="Ia"|dat$fac13[i]=="Ib"|dat$fac13[i]=="Ic", dat$Y[i]<-rbinom(1,1,0.75), dat$Y[i]<-rbinom(1,1,0)) } dat$Y<-as.factor(dat$Y) tr<-ctree(Y~fac1+fac2+fac3,data=dat) plot(tr) ###################################################################################### ----- ------------------------ Kay Cichini Postgraduate student Institute of Botany Univ. of Innsbruck ------------------------ -- View this message in context: http://r.789695.n4.nabble.com/logistic-regression-tree-tp2331847p2333073.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.