Stratified sampling methods

A question is this type if and only if it asks to explain, describe, or calculate sample sizes for stratified sampling based on population subgroups.

3 questions · Easy -1.6

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Edexcel S3 2024 January Q2
7 marks Easy -1.8
  1. A company has 800 employees.
The manager of the company is going to take a sample of 80 employees.
  1. 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.
    CityLondonEdinburghCardiff
    Number of employees430250120
    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.
  2. Explain how this sample can be taken using stratified sampling.
  3. Explain an advantage of using stratified sampling rather than simple random sampling.
Edexcel S3 2016 June Q3
6 marks Easy -1.2
3. A company wants to survey its employees' attitudes to work. The company's workforce is located at three offices. The number of employees at each location is summarised in the table below.
Office locationNumber of employees
Bristol856
Dudley429
Glasgow1215
Each employee is located at only one office. A personnel assistant plans to survey the first 50 employees who arrive for work at the Bristol office on a Monday morning.
  1. Give two reasons why this survey is likely to lead to a biased response. A personnel manager has access to the company's information system that holds details of each employee including their place of work. The manager decides to take a stratified sample of 150 employees.
  2. Describe how to choose employees for this stratified sample.
  3. Explain an advantage of using a stratified sample rather than a quota sample.
Edexcel S3 Q1
5 marks Easy -1.8
  1. A personnel manager has details on all company employees and wishes to consult a sample of them on a possible change to the company's hours of business. She decides to take a stratified sample based on different age groups.
    1. Give one advantage of using stratified sampling in this situation.
    The manager needs to select a sample of size 10 , without replacement, from a list of 65 employees aged 16 to 25 . She numbers these employees from 01 to 65 in alphabetical order and uses the table of random numbers given in the formula book. She starts with the top of the sixth two-digit column and works down. The first two numbers she writes down are 30 and 47.
  2. Find the other eight numbers in the sample.
  3. Suggest another factor that might be useful to consider in deciding on the strata.
    (1 mark)