单项选择题
麦当劳餐馆在1个月内抽查64位顾客的消费额如下:
消费额(元) | 10~20 | 20~30 | 30~40 | 40~50 | 50以上 | 总计 |
顾客人数(人) | 11 | 25 | 15 | 10 | 3 | 64 |
据以计算样本平均数和用以代替总体方差的抽样方差:

=30.16:s
2=120.61;s=10.98
该餐馆顾客消费额的抽样平均误差:
(甲)

(元);
(乙)

(元)。
消费20至30元的比重(p=25/64=0.39)抽样平均误差:
(丙)

;
(丁)

;
A.甲丙 B.甲丁 C.乙丙 D.乙丁
A.174.24.96:6088/Latex/latex.action?latex=XGJhcnt4fQ%3D%3D'
B.16:s2=120.61;s=10.98
C.174.24.96:6088/Latex/latex.action?latex=XHNxcnR7XHNpZ21hIF4yL259PVxzcXJ0ezEyMC42MS82NH09MS4zNw%3D%3D'
D.174.24.96:6088/Latex/latex.action?latex=XHNxcnR7XHNpZ21hIC9ufT1cc3FydHsxMC45OC82NH09MC40MQ%3D%3D'
E.39)抽样平均误差:
F.174.24.96:6088/Latex/latex.action?latex=XHNxcnR7UCgxLVApL259PVxzcXJ0eygwLjM5XHRpbWVzIDAuNjEpLzY0fT02LjEl'
G.174.24.96:6088/Latex/latex.action?latex=XHNxcnR7UCgxLVApfT1cc3FydHswLjM5XHRpbWVzIDAuNjF9PTQ5JQ%3D%3D'
H.甲丙
I.甲丁
J.乙丙