On Mon, Dec 3, 2012 at 3:30 PM, tdbuskirk <trent.busk...@nielsen.com> wrote: > > Hello R Gurus, > > I am perplexed by the different results I obtained when I ran code like > this: > set.seed(100) > test1<-randomForest(BinaryY~., data=Xvars, trees=51, mtry=5, seed=200) > predict(test1, newdata=cbind(NewBinaryY, NewXs), type="response") >
Not sure about this since I haven't used predict.randomForest extensively, but newdata usually contains predictors only, not the response. Try using newdata = NexXs. HTH, Peter > and this code: > set.seed(100) > test2<-randomForest(BinaryY~., data=Xvars, trees=51, mtry=5, seed=200, > xtest=NewXs, ytest=NewBinarY) > > The confusion matrices for the two forests I thought would be the same by > virtue of the same seed settings, but they differ as do the predicted > values > as well as the votes. At first I thought it was just the way ties were > broken, so I changed the number of trees to an odd number so there are no > ties anymore. > > Can anyone shed light on what I am hoping is a simple oversight? I just > can't figure out why the results of the predictions from these two forests > applied to the NewBinaryYs and NewX data sets would not be the same. > > Thanks for any hints and help. > > Sincerely, > > Trent Buskirk > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/Different-results-from-random-Forest-with-test-option-and-using-predict-function-tp4651970.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. ______________________________________________ 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.
