Statistics Questions Metropolitan Research, Inc., a consumer research organization, conducts surveys designed to evaluate a wide variety of products and services available to consumers. In one particular study, Metropolitan looked at consumer satisfaction with the performance of automobiles produced by a major Detroit manufacturer. A questionnaire sent to owners of one of the manufacturer’s full-sized cars reviewed several complaints about early transmission problems. Nationwide, the populations mean mileage, µ, is 80,000 miles, with a population standard deviation, σ, of 18,000 miles. To learn more about the transmission failures, Metropolitan used a sample of actual transmission repairs provided by a transmission repair firm in the...The end:
..... .01); the mean mileage of vehicles produced by this manufacturer is indeed lower than the national average mileage at transmission failure. 5. Assuming 90% confidence, what is the recommended sample size if the desired margin of error is 1,000 miles? Would it be reasonable to obtain this sample size? Why/why not? In order to obtain this answer, the margin of error first had to be transformed into percent. A margin of error of 1,000 miles given a population mean of 80,000 miles is 1,000/80,000, or 1.25%. At a confidence level of 90% and assuming a population of over 20,000, the recommended sample size is 3,559. It would not be reasonable to obtain this sample size because of the resources involved in assessing this large number of vehicles.