Practical Exercise
A local leisure and sports club has been trying to increase the number of customers using the club. Customers have to
join the club as members and pay a small annual fee together with a fee for each time they use the club. A special marketing campaign has been introduced to try to increase the number of customers using the club. For a comparable
period of 2 months before the campaign and for a period of 2 months after the campaign the club has monitored the number of customers using the club each day. The club has asked you to report on what changes in customer usage have occurred.
i. Based on the statistics shown, outline the main similarities and differences in customer numbers pre– and post– campaign.
ii. Calculate a 95% confidence interval for the true mean number of customers post–campaign. Explain what the interval shows.
iii. Calculate a 99% confidence interval for the true mean number of customers post–campaign. Explain how interval differs from the one computed in part (ii).
