Hoping to improve customer service, a retailer sent a sample of 85 salespeople to a training program that emphasized self-image, respect for others, and manners. Management decided that if the rate of...

Hoping to improve customer service, a retailer sent a sample of 85 salespeople to a training program that emphasized self-image, respect for others, and manners. Management decided that if the rate of complaints fell below 10% per month after the training (fewer than 10 complaints per 100 employees), it would judge the program a success. Following the program, complaints were received for 6% of the 85 employees who participated.

a. State the null hypothesis and the alternative hypothesis.¹⁰

b. Identify the relevant sample statistic.¹¹

c. Describe a model for the sampling distribution of the test statistic if, in the full population, 10% of employees generate complaints.¹²