1 PROC MEANS OPTIONS; /*默认输出：非缺省数目、均值、标准差、最小值、最大值*/2     BY variable-list;/*必须要预先排序*/3     CLASS variable-list;/*功能与BY语句相同，不需要预先排序*/4      VAR variable-list;5      OUTPUT OUT=data-set statistic(variable-list)=name-list; /*除了VAR与语句中的变量名外，还有两变量：_TYPE_和_FREQ_*/6                                        /*例：MEAN(Lions Bears)=Lionweight Bearweight*/