打个比方说给了x1-x11共11个变量，对其做判别分析，主要语言如下：proc sort data=b;
by group;
proc means data=b;
var x1 x2 x3 x4 x5 x6 x7 x8 x9 x10 x11;
by group;
run;
proc candisc out=result ncan=2;
class group;
var x1-x11;
run;
proc discrim data=result distance list;
class group;
var can1 can2;
run;

如何选择变量？如何使错误率降低？
我是新学SAS的求各位大神指导，提前说声谢谢了。