8. During September 2018, United Airlines introduced a new two-line boarding process intended to decrease gate congestion, passenger anxiety, and time to board the plane. Independent random samples of similar cross-country ights for United Airlines and American Airlines were obtained and the boarding time (in minutes) for each was recorded. Assume both populations are normally distributed and the population standard deviations are unequal. Sample Size Sample Mean Sample Standard Deviation a) Find a 99% condence interval for the difference in boarding time between the two airlines. b) Does the condence interval produced in part a suggest at the 1% level that the mean boarding time is different for the two airlines? How do you know