The accompanying data on seat belt use for each of the 50 U.S. states and the District of Columbia are from “Traffic Safety Facts,” (National Highway Traffic Safety Administration, June 2015). The observations represent the percentage of drivers wearing seat belts in a large nationwide observational survey.

95.7 88.4 87.2 74.4 97.1 82.4 85.1 91.9 93.2 88.8 97.3 93.5 80.2 94.1 90.2 92.8 85.7 86.1 84.1 85.0 92.1 76.6 93.3 94.7 78.3 78.8 74.0 70.0 94.0 70.4 87.6 92.1 90.6 90.6 81.0 85.0 86.3 97.8 83.6 87.4 90.0 68.9 87.7 90.7 83.4 84.1 77.3 94.5 87.8 84.7 79.2 

a. The values in the data set range from 68.9% to 97.8%. Construct a stem-and-leaf display that uses repeated stems 6H, 7L, 7H, … 9H. 

b. Write a few sentences commenting on what the stem-and-leaf display suggests about seat belt use.