Refer to Exercise 1.25. In 2004, the number of vehicles registered grew to 235.4 million from 230.9 million in 2003. Vehicle miles traveled increased from 2.89 trillion in 2003 to 2.92 trillion in 2004. Answer the following questions and explain your answers.
a. Are the numbers of registered vehicles descriptive statistics or inferential statistics?
b. Are the vehicle miles traveled descriptive statistics or inferential statistics?
c. How do you think the NHTSA determined the number of vehicle miles traveled?
d. The highway fatality rate dropped from 1.48 deaths per 100 million vehicle miles traveled in 2003 to 1.46 deaths per 100 million vehicle miles traveled in 2004. It was the lowest rate since records were first kept in 1966. Are the highway fatality rates descriptive statistics or inferential statistics?