> NMSE=rep(0,5);NMSEO=NMSE
>  for(i in 1:5){
+    m=zz1[zz2==i]
+    a<-lm(订单~.,data=w)
+    y0=predict(a,w[-m,]);y1=predict(a,w[m,])
+    NMSEO(i)=mean((w$订单[-m]-y0)^2)/mean((w$订单[-m]-mean(w$订单[-m]))^2)
+    NMSE[i]=mean((w$订单[m]-y1)^2)/mean((w$订单[m]-mean(w$订单[m]))^2)}
Error: object 'zz1' not found
>   (MNMSE)=mean(NMSE0));(MNMSE=mean(NMSE))
Error: unexpected ')' in "  (MNMSE)=mean(NMSE0))"