Given the existing SAS program:
proc format;
value agegrp
low-12 =’Pre-Teen’
13-high = ‘Teen’;
run;
proc means data=SASHELP.CLASS;
var Height;
class Sex Age;
format Age agegrp.;
run;
Which statement in the proc means step needs to be modified or added to generate the following results:
| Analysis Variable : Height | |||||
| Sex | Age | N Obs | Minimum | Maximum | Mean |
| F | Pre-Teen | 3 | 51.3 | 59.8 | 55.8 |
| Teen | 6 | 56.5 | 66.5 | 63.0 | |
| M | Pre-Teen | 4 | 57.3 | 64.8 | 59.7 |
| Teen | 6 | 62.5 | 72.0 | 66.8 | |
A. var Height / nobs min max mean maxdec=1;
B. proc means data=SASHELP.CLASS maxdec=1 ;
C. proc means data=SASHELP.CLASS min max mean maxdec=1;
D. output nobs min max mean maxdec=1;
Answer: C
注解：PROC MEANS默认会输出非missing观测值个数、均值、标准差、最小值和最大值。题目只需要输出最小值（MIN）、最大值（MAX）和均值（MEAN），并显示小数点后一位（MAXDEC）。其中N Obs是观测值个数（包括missing和非missing），要去掉的话使用NONOBS，即proc means data = XXXX nonobs。