# Question: Two competing airlines Alpha and Beta fly a route between

Two competing airlines, Alpha and Beta, fly a route between Des Moines, Iowa, and Wichita, Kansas. Each airline claims to have a lower percentage of flights that arrive late. Let p1 be the proportion of Alpha’s flights that arrive late and p2 the proportion of Beta’s flights that arrive late.

a. You are asked to observe a random sample of arrivals for each airline to estimate p1 – p2 with a 90% confidence level and a margin of error of estimate of .05. How many arrivals for each airline would you have to observe? (Assume that you will observe the same number of arrivals, n, for each airline. To be sure of taking a large enough sample, use p1 = p2 = .50 in your calculations for n.)

b. Suppose that p1 is actually .30 and p2 is actually .23. What is the probability that a sample of 100 flights for each airline (200 in all) would yield p̂1 > p̂2?

a. You are asked to observe a random sample of arrivals for each airline to estimate p1 – p2 with a 90% confidence level and a margin of error of estimate of .05. How many arrivals for each airline would you have to observe? (Assume that you will observe the same number of arrivals, n, for each airline. To be sure of taking a large enough sample, use p1 = p2 = .50 in your calculations for n.)

b. Suppose that p1 is actually .30 and p2 is actually .23. What is the probability that a sample of 100 flights for each airline (200 in all) would yield p̂1 > p̂2?

## Answer to relevant Questions

Refer to Exercise 10.56, in which a random sample of six cars was selected to test a gasoline additive. The six cars were driven for 1 week without the gasoline additive and then for 1 week with the additive. The data ...Repeat Problem 4 assuming that the times spent per week playing with their children by all alcoholic and all nonalcoholic fathers both are normally distributed with unequal and unknown standard deviations. In Problem 4 A ...The October 2011 ISACA Shopping on the Job Survey asked employees, “During the holiday season (November and December), how much total time do you think an average employee at your enterprise spends shopping online using a ...Explain how the expected frequencies for cells of a contingency table are calculated in a test of independence or homogeneity. How do you find the degrees of freedom for such tests? National Electronics Company buys parts from two subsidiaries. The quality control department at this company wanted to check if the distribution of good and defective parts is the same for the supplies of parts received ...Post your question