search for: drugusey

...able. e.g. Breiman Olshen et al. Classification and Regression Trees state "In a standard data structure [a tree] is invariant under all monotone transformations of individual ordered varaibles" (p. 57) However, I get very different results from tr.hh.pri <- rpart((log(YPRISX+1)~AGE+DRUGUSEY+SEX+OBSXNUM)) and tr.hh.pri <- rpart(YPRISX~AGE+DRUGUSEY+SEX+OBSXNUM) the former gives more splits and different splits. Some notes: The DV is a count variable, and highly skew, with some 0s, many 1s, and a long right tail out to 99. AGE ranges from 18-25 DRUGUSEY is ordered (hardest drug u...

Hello I am running R 1.8.1 on a Windows platform I am attempting to fit an ordinal logistic regression model, using the polr function, as described in Venables and Ripley. But when I try model4 <- polr(ypsxcat~committed + as.factor(sex) + as.factor(drugusey) + anycsw + as.factor(sex)*committed + as.factor(sex)*as.factor(drugusey)+as.factor(sex)*anycsw, data = duhray) I get a message that the polr function was not found. Any help appreciated thanks Peter Peter L. Flom, PhD Assistant Director, Statistics and Data Analysis Core Center for Drug U...

I have a tree created with tr.hh.logcas <- rpart(log(YCASSX + 1)~AGE+DRUGUSEY+SEX+OBSXNUM +WINDLE, xval = 10) I would like to label the nodes with YCASSX rather than log(YCASSX + 1). But the help file for text in library rpart says that you can only use labels that are part of x$frame, which YCASSX is not. Is there a way to do what I want? Thanks in advance Peter Peter...