he president of a company that manu-factures automobile air conditioners is consideringswitching his

he president of a company that manu-factures automobile air conditioners is consideringswitching his supplier of condensers. Supplier A, thecurrent producer of condensers for the manufacturer,prices its product5% higher than supplier B. Becausethe president wants to maintain his company’sCopyright 2014 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.459INFERENCE ABOUT COMPARING TWO POPULATIONSreputation for quality, he wants to be sure that sup-plier B’s condensers last at least as long as supplier A’s.After a careful analysis, the president decided to retainsupplier A if there is sufficient statistical evidence thatsupplier A’s condensers last longer on average thansupplier B’s. In an experiment,30 midsize cars wereequipped with air conditioners using type A condens-ers while another 30 midsize cars were equippedwith type B condensers. The number of miles (inthousands) driven by each car before the condenserbroke down was recorded. Should the president retainsupplier A