Question

In a study investigating the effect of car speed on accident severity, 5,000 reports of fatal automobile accidents were examined, and the vehicle speed at impact was recorded for each one. For these 5,000 accidents, the average speed was 46 mph and the standard deviation was 13 mph. A histogram revealed that the vehicle speed at impact distribution was approximately normal. (Use the Empirical Rule.)

(a)

Approximately what percentage of these vehicle speeds were between 33 and 59 mph?

approximately _________ %

(b)

Approximately what percentage of these vehicle speeds exceeded 59 mph? (Round your answer to the nearest whole number.)

approximately _________%

(C) A student took two national aptitude tests. The national mean and standard deviation were 575 and 100, respectively, for the first test, and 30 and 10, respectively, for the second test. The student scored 675 on the first test and 45 on the second test. Use z-scores to determine on which exam the student performed better relative to the other test takers.

Answer 1