题目
A company has 800 employees. The manager of the company is going to take a sample of 80 employees.
(a) Explain how this sample can be taken using systematic sampling.
The company has offices in London, Edinburgh and Cardiff. The table shows the number of employees in each city.
| City | London | Edinburgh | Cardiff |
|---|---|---|---|
| Number of employees | 430 | 250 | 120 |
The president of the company is going to take a sample of 100 employees to determine the average time employees spend in front of a computer each week.
(b) Explain how this sample can be taken using stratified sampling.
(c) Explain an advantage of using stratified sampling rather than simple random sampling.
题目中文翻译
一家公司的员工共有 800 人。 公司经理准备抽取 80 名员工作为样本。
(a) 说明如何使用系统抽样抽取这个样本。
公司在伦敦、爱丁堡和卡迪夫都有办公室。下表给出了各城市的员工人数。
| 城市 | 伦敦 | 爱丁堡 | 卡迪夫 |
|---|---|---|---|
| 员工人数 | 430 | 250 | 120 |
公司总裁准备抽取 100 名员工，以确定员工每周花在电脑前的平均时间。
(b) 说明如何使用分层抽样抽取这个样本。
(c) 说明与简单随机抽样相比，分层抽样的一个优点。