even.n=2*(1:75)-1

> x.train=x[even.n,]

> x.test=x[-even.n,]

> x.rp2=rpart(lifetime~frequency+completion+number,x.train,method="class")

> x.rp2=rpart(lifetime~frequency+completion+number,x.train,method="class")

> x.rp3=predict(x.rp2,x.test[,-5],type="class")

Error in eval(expr, envir, enclos) : object 'completion' not found