有5个组A，B，C，D，E，数据也按字母顺序给出。C为对照组，在使用如下方法时：

proc anova data=ex9_0;                                                                                                             
   class X;                                                                                                                            
   model Y = X;                                                                                                                        
   means X / HOVTEST=BF;                                                                                                               
   means x / DUNNETT;                                                                                                                  
run; quit;

结果总是与A进行的对比，请问怎么做才能是其他组和C组做对比呀？

还有用TUKEY方法进行5组之间两两对比，怎么做呀？

请大家指教下，谢谢了！！