A supermarket chain has 93 stores in the United Kingdom with a total of 4502 employees. Each store is either a large store or a small store.
The directors of the supermarket chain are proposing to make changes to the employees’ working hours. The directors want to survey a sample of 450 employees from the total workforce in order to ask them for their views on the proposed changes.
Three possible sampling methods in order to select the employees to be in the survey are suggested.
Method A The directors will choose two employees from each small store and six employees from each large store.
Method B All 4502 employees are allocated a number from 0001 to 4502 Start with number 0010 and take every 10th employee so that the sample consists of employees with the numbers 0010, 0020, 0030, … and 4500
Method C Each employee in each store will be given a raffle ticket and 10% of the number of employees in each store will be chosen at random by taking raffle tickets out of boxes, one box for each store.
For each of the three methods, identify the sampling method and discuss whether the sampling method is an appropriate way to select the employees to be in the survey.
As part of your discussion you should also state, with reasons, which of the three sampling methods is the most appropriate method for the directors to use.