题目内容:
A process characteristic has a true (population) mean of 150 and a true (population) standard deviation of 20.A sample of 25 items is taken from this process.The standard deviation of the sample is:( )A.0.2
B.0.8
C.4.0
D.5.0 A.0.2
B.0.8
C.4.0
D.5.0
参考答案:
答案解析: