程序如下：
proc mixeddata=bone covtest ic;
class id year group;
model tbmt=group| year agef_sex1 mc1_a mc2_a ca_a fe_a nation1 baeduc maeduc bmi height/s ;
random int year/ subject=id ;
repeated year / subject=id ;
lsmeans year*group /adjust=bon;
by sex;
run;
日志提示：

NOTE: 122 observations are not included because of missing values.
NOTE: Convergence criteria met.
NOTE: 上述消息是针对以下 BY 组的:
sex=1
NOTE: 117 observations are not included because of missing values.
NOTE: Convergence criteria met.
NOTE: 上述消息是针对以下 BY 组的:
sex=2
NOTE: “PROCEDURE MIXED”所用时间（总处理时间）:
实际时间 0.29 秒
CPU 时间 0.31 秒