IQ = c(rep(1,497),rep(2,651))
Y = Y[,1:2]
lda.IQ = lda(Y,IQ); lda.IQ
lda.pred = predict(lda.IQ)
attributes(lda.pred)
lda.pred$class
head(lda.pred$posterior)
table(lda.pred$posterior[,1]>lda.pred$posterior[,2],lda.pred$class)
table(IQ,lda.pred$class) #40 chilren misclaasified
partimat(IQ~Y[,1]+Y[,2],method='lda',imageplot=FALSE)

Error in partimat.default(x, grouping, ...) :
at least two classes required