用下面的程序作图,如何加置信带啊?谢谢!
ods graphics on;
proc phreg data=af_c_his plots(overlay)=survival;class age_st_stra(ref='age <= 70 & ST before AF');
model age_f_c_t_sthis*st_c_his(0)=age_st_stra/rl=wald;
baseline covariates=age_st_stra;run;
ods graphics off;