NHTSA new car crash tests. Refer to the National Highway Traffic Safety Administration (NHTSA) crash test data for new cars In Exercise 8.101 (p. 490) you compared the chest injury ratings of drivers and front-seat passengers using the Student’s t-procedure for matched pairs. Suppose you want to make the comparison for only those cars that have a driver’s star rating of 5 stars (the highest rating). The data for these 18 cars are listed in the next table. Now consider analyzing these data using the Wilcoxon signed rank test. Chest Injury Rating Car Driver Passenger 1 42 35 2 42 35 3 34 45 4 34 45 5 45 45 6 40 42 7 42 46 8 43 58 9 45 43 10 36 37 11 36 37 12 43 58 13 40 42 14 43 58 15 37 41 16 37 41 17 44 57 18 42 42

a. State the null and alternative hypotheses.

b. Use a statistical software package to find the signed rank test statistic.

c. Give the rejection region for the test using a = .01.

d. State the conclusion in practical terms. Report the p-value of the test.