Consider testing the hypothesis of equal population means based on the data in the previous exercise.

Data From previous exercise

a. Carry out a two-tailed test using the method of Section 10.3. Is the normality assumption satisfied here? If not, why might the test be valid anyway?

b. Carry out a two-tailed permutation test for the hypothesis of equal population means.

c. Compare the results for (a) and (b). If the two results are similar, does it tend to validate (a), regardless of normality?

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Two students, Miguel Melo and Cody Watson, compared textbook prices at the campus bookstore and Amazon.com. To be fair, they included the sales tax for the local store and added shipping for Amazon. Here are the prices for a sample of 27 books. Campus 100.41 99.34 51.53 20.45 28.69 70.66 98.81 111.56 Amazon 106.94 113.94 61.44 31.59 29.89 83.94 107.74 115.99 Campus Amazon 97.22 108.29 61.89 78.44 70.39 82.94 58.17 65.74 122.09 63.49 108.38 61.63 Campus 59.50 87.66 26.56 44.63 96.69 18.06 103.06 14.61 Campus 77.03 99.34 81.81 48.88 76.50 Amazon 69.24 73.84 33.98 40.39 117.99 27.94 115.74 24.69 Amazon 88.04 113.94 90.74 58.94 91.94