Basic Marketing Research 7th Edition by Gilbert Churchill,Tom Brown,Tracy Suter

Exercise 2

A survey was being designed by the marketing research department of a medium-sized manufacturer of household appliances. The general aim was to assess customer satisfaction with the company's dishwashers. As part of this general objective, management wanted to measure the average maintenance expenditure per year per household, the average number of malfunctions or breakdowns per year, and the number of times a dishwasher is cleaned within a year. Management wished to be 95% confident in the results. Furthermore, the magnitude of the error was not to exceed +/-$4 for maintenance expenditures, +/-1 for malfunctions, and +/-4 for cleanings. The research department noted that while some households would spend nothing on maintenance expenditures per year, others might spend as much as $120. Also, while some dish-washers would experience no breakdowns within a year, the maximum expected would be no more than three. Finally, while some dishwashers might not be cleaned at all during the year, others might be cleaned as frequently as once a month.
a. How large a sample would you recommend if each of the three variables were considered separately Show all your calculations.
b. What size sample would you recommend overall given that management felt that the expenditure on repairs was most important and the number of cleanings least impor-tant to know accurately