A SAS PRINT procedure output of the WORK.LEVELS data set is listed below:
Obsname level
1 Frank 1
2 Joan 2
3 Sui 2
4 Jose 3
5 Burt 4
6 Kelly .
7 Juan 1
The following SAS program is submitted:
data work . expertise;
set work. levels;
if level = . then
expertise = 'Unknown';
else if level = 1 then
expertise = 'Low';
else if level = 2 or 3 then
expertise =' Medium';
else
expertise = 'High';
run;

为啥Burt的level4 没有显示出high呢？