[EX02-192] The national highway system is made up of interstate and noninterstate highways.

The Federal Highway Administration reported the number of miles of each type in each state. Listed is a random sample of 20.

Miles of Interstate and Noninterstate Highways by State State Interstate Noninterstate State Interstate Noninterstate NE 235 590 TN 1,073 2,171 FL 1,471 2,897 NJ 1,000 1,935 MA 367 924 LA 904 1,701 HI 55 291 TX 3,233 10,157 MT 1,192 2,683 OH 1,574 2,812 MN 912 3,060 IN 782 2,434 GA 1,245 3,385 NM 1,674 3,476 OK 930 2,431 NC 482 2,496 NV 1,019 2,743 AR 1,167 1,566 RI 71 198 DE 13 70 Source: Federal Highway Administration, U.S. Department of Transportation Define “ratio I/N” to be number of interstate miles divided by number of noninterstate miles.

a. Inspect the data. What do you estimate the

“average” ratio I/N to be?

b. Calculate the “ratio I/N” for each of the 20 states listed.

c. Draw a histogram of the “ratio I/N.”

d. Calculate the mean “ratio I/N” for the 20 states listed.

e. Use the 20-state total number of interstate and noninterstate miles to calculate the “ratio I/N”

for the combined 20 states.

f. Explain why the answers to parts d and e are not the same.

g. Calculate the standard deviation for the “ratio I/N” for the 20 states listed.

h. The number of miles of interstate and noninterstate highway for all 50 states and Washington, DC, is listed on your CD. Answer the questions in parts b through g using all 51 values.

(Optional.) [DS02-192]