In the airline business, “on-time” flight arrival is important for connecting flights and general customer satisfaction. Is there a difference between summer and winter average on-time flight arrivals? Let x1 be a random variable that represents percentage of on-time arrivals at major airports in the summer. Let x2 be a random variable that represents percentage of on-time arrivals at major airports in the winter. A random sample of n1 =16 major airports showed that 1 = 74.8%, with s1 = 5.2%. A random sample of n2 = 18 major airports showed that 2 = 70.1%, with s2 = 8.6%.
(a) Does this information indicate a difference (either way) in the population mean percentage of on time arrivals for summer compared to winter? Use α = 0.05.
(b) Find an 95% confidence interval for µ1 − 2 µ2.
(c) What assumptions about the original populations have you made for the methods used?