Rebecca Sims Is the General Manager of a Chain of Auto

Multiple Choice

Rebecca Sims is the general manager of a chain of auto parts stores. There are 400 stores in the country and they are divided up into seven divisions based upon geography. Each division has a division manager. The firm prides itself on keeping close tabs on customer satisfaction, and Rebecca has decided to take a sample of the 400 to test a new surrogate measure of customer satisfaction; the dollar value of returned merchandise. Each sample store reports daily the dollar value of merchandise returned and an average is calculated for each division. When Rebecca sees the first set of results, she wants to know if the differences between the division means are real or due to sampling error. Rebecca should use which test?

A) a z test of the difference between two percentages
B) independent samples t test
C) paired samples t test
D) ANOVA
E) a division differences test