Hi, I think I'm missing something very obvious, but I am missing it, so I would be very grateful for help. I'm using rpart to analyse data on skull base morphology, essentially predicting sex from one or several skull base measurements. The sex of the people whose skulls are being studied is known, and lives as a factor (M,F) in the data. I want to get back predictions of gender, and particularly misclassification rates.
rpart produces output like this :- > printcp(rpart.LFM) Classification tree: rpart(formula = Sex ~ LFM, data = Brides2) Variables actually used in tree construction: LFM Root node error: 44/104 = 0.42308 n= 104 CP nsplit rel error xerror xstd 1 0.227273 0 1.00000 1.00000 0.11451 2 0.113636 1 0.77273 0.95455 0.11372 3 0.022727 2 0.65909 0.95455 0.11372 4 0.010000 5 0.59091 0.95455 0.11372 > Presumably 'root node error' and 'rel error' are something to do with error but what? 'Root node error ' seems to be some sort of deviance, and I have no idea what 'rel error' is. the tree library does produce a simple estimate of misclassification, but rpart doesn't seem to. Any ideas? Thanks, Anthony Staines -- Dr. Anthony Staines, Senior Lecturer in Epidemiology. School of Public Health and Population Sciences, UCD, Earlsfort Terrace, Dublin 2, Ireland. Tel:- +353 1 716 7345. Fax:- +353 1 716 7407 Mobile:- +353 86 606 9713 Web:- http://phm.ucd.ie ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html