[R] knncat question

[Aimin Yan]

I use knncat to make a predictive model
and get misclass rate
 > knncat.m<-knncat(training.new,k=c(10,20),classcol=5)
 > knncat.m
Training set misclass rate: 36.88%

then I try to calculate prediction accuracy by the following:

 > pr.knncat.train <- predict 
(knncat.m,training.new,training.new,train.classcol=5,newdata.classcol=5)
 > tb.knncat.train <-table (pr.knncat.train, training.new$y)
 > nnb.accuracy.train<-round(sum(diag(tb.knncat.train))/sum(tb.knncat.train),2)
 > cat("NNB prediction accuracy for training",nnb.accuracy.train,"\n")
NNB prediction accuracy for training 0.67

I thought I should to get :
100%-36.88%=63.12%=0.63.

But in my calculation, I get 0.67.
Is my calculation wrong?

thanks,

Aimin