webgu 发表于 2012-5-5 22:20 
data dstst;
set dstst;
dum1=(smoking=1);/*1为不吸烟*/
data dstst;
set dstst;
dum1=(smoking=1);/*1为不吸烟*/
dum2=(smoking=2);/*2为偶尔吸烟*/
run;
data dstst;
set dstst;
dum1=(smoking=2);/*2为偶尔吸烟*/
dum2=(smoking=3);/*3为经常吸烟*/
run;
data dstst;
set dstst;
dum1=(smoking=1);/*1为不吸烟*/
dum2=(smoking=3);/*3为经常吸烟*/
run;
三者有什么区别呢 怎么选择啊 求解