题目
An internet service provider is going to carry out a sample survey of its customers to investigate how satisfied customers are with their download speed.
(a) For this survey
(i) suggest a suitable sampling frame,
(ii) identify the sampling units.
(b) Give one advantage of taking a sample rather than a census.
A large number of customers completed the survey and 35% said they were satisfied with their download speed.
A random sample of 50 customers who completed the survey is taken.
(c) Write down a suitable distribution to model the number of customers in this sample that were satisfied with their download speed.
Using your answer to part (c)
(d) find the probability that more than 40% of the customers in the sample were satisfied with their download speed.
(Total for Question 1 is 7 marks)
题目中文翻译
一家互联网服务提供商将对其客户进行抽样调查，以了解客户对其下载速度的满意程度。
(a) 对于此调查
(i) 建议一个合适的抽样框架，
(ii) 识别抽样单位。
(b) 给出抽样而非普查的一个优点。
大量客户完成了调查，其中 35% 表示对下载速度满意。
随机抽取了 50 名完成调查的客户样本。
(c) 写出一个合适的分布来建模此样本中对下载速度满意的客户数量。
使用你在 (c) 中的答案
(d) 求样本中超过 40% 的客户对下载速度满意的概率。
（第 1 题共 7 分）