webgu 发表于 2012-9-23 09:56 
这样?
proc ttest data=cars(where=(reliabe=1 or 3));
class reliable;
不行啊亲
8 proc ttest data=cars(where=(reliable=1 or 3));
9 class reliable;
10 var millage;
11 run;
NOTE: Writing HTML Body file: sashtml.htm
ERROR: The CLASS variable has more than two levels.