10, Dec 2020
Find a 96% confidence interval for the difference in the number of traffic accidents

A number of minor automobile accidents occur at various high–risk intersections in Iron
County. The traffic department claims that a modification in the type of light will reduce these accidents. The county commissioners have agreed to a proposed experiment.
Eight intersections were chosen at random, and the lights at those intersections were
modified. The number of minor accidents during a six–month period before and after
installing traffic signals were:
Number of Minor Accidents
intersection A B C D E F G H
before 5 7 6 4 8 9 8 10
after 3 7 7 0 4 6 8 6
Find a 96% confidence interval for the difference in the number of traffic accidents