5.10 Hoskin et al. (1986) investigated the change in fatal motor-vehicle accidents after the legal minimum drinking age was raised in 10 states.

Their data were the ratios of the number of single-vehicle nighttime fatalities to the number of licensed drivers in the affected age group before and after the laws were changed to raise the drinking age, shown below. The researchers hypothesized that raising the minimum drinking age resulted in a reduced median fatality ratio. Investigate this hypothesis.

State Affected Ages Ratio Before Ratio After Florida 18 0.262 0.202 Georgia 18 0.295 0.227 Illinois 19–20 0.216 0.191 Iowa 18 0.287 0.209 Maine 18–19 0.277 0.299 Michigan 18–20 0.223 0.151 Montana 18 0.512 0.471 Nebraska 19 0.237 0.151 New Hampshire 18–19 0.348 0.336 Tennessee 18 0.342 0.307