找了半天,终于弄明白了,这个问题还是很能迷惑人的.

在sas中关于or是这样说明的:

Remember that only one comparison in a series of OR comparisons must be true to make a condition true, and any nonzero, nonmissing constant is always evaluated as true (see Boolean Numeric Expressions). Therefore, the following subsetting IF statement is always true:

if x=1 or 2;

SAS first evaluates X=1, and the result can be either true or false; however, since the 2 is evaluated as nonzero and nonmissing (true), the entire expression is true.

因为后面2是一个常数且不为0,所以整个表达式都为真,那么后面都执行同样的操作.

所以如果你的题目想要包含"high",那么应该改为:

~~~

else if level = 2 or level=3 then

expertise =' Medium';

~~~~~~~~~~

The following SAS program is submitted:

data test;

set sasuser.employees;

if 2 le years_service le 10 then

amount=1000;

else if years_service gt 10 then

amount=2000;

else

amount=0;

amount_per_year=years_serice/amount;

run;

Which one of the following values does the variable AMOUNT_PER_YEAR contain

if an employee has been with the company for one year?

A. 0

B. 1000

C. 2000

D. . (missing numeric value)

Yes. You are right. 0 不能作分母， 所以商是missing.

The contents of the raw data file SIZE are listed below:

----|----10---|----20---|----30

72 95

The following SAS program is submitted:

data test;

in file 'size';

input@ 1 height 2.@ 4 weight 2;

run;

Which one of the following is the value of the variable WEIGHT in the output data set?

A. 2

B. 72

C. 95

D. . (missing numeric value)

Answer:A
I know the problem is to omit the period.SAS assign a length of 2 to weight instead of reading weight with the 2 informat.
I would like to ask why the value of the variable WEIGHT is 2?