9. b Some college students did a study of textbook pricing. They compared prices at the campus bookstore and Amazon.com for the same price. To be fair, they included the sales tax for the local store and the added shipping form Amazon. Here are the prices for a sample of 10 books. (a) We want to determine if there is a signicant difference in the price of textbooks from the campus bookstore and from Amazon.com. Which type of test would we use for this data? (b) Determine a 95% condence interval for the difference of the population means. (c) Interpret your results. Is there a substantial difference between the two ways to be textbook? Assuming that the populations remain unchanged and you have just these two sources, where would you buy