The president of a company that manufactures automobile air conditioners is considering switching his supplier of condensers. Supplier A, the current producer of condensers for the manufacturer, prices its product 5% higher than supplier B. Because the president wants to maintain his company’s reputation for quality, he wants to be sure that supplier B’s condensers last at least as long as supplier A’s.
After a careful analysis, the president decided to retain supplier A if there is sufficient statistical evidence that supplier A’s condensers last longer on average than supplier B’s. In an experiment, 30 midsize cars were equipped with air conditioners using type A condensers while another 30 midsize cars were equipped with type B condensers. The number of miles (in thousands) driven by each car before the condenser broke down was recorded. Should the president retain supplier A?