were chosen at random, and the traffic lights of those intersections were modified. The numbers of minor accidents during a six-month period before and after the modifications were:
NUMBER OF ACCIDENTS
A - B - C - D - E - F - G - H
5 - 7 - 6 - 4 - 8 - 9 - 8 - 10 (BEFORE MODIFICATION)
3 - 7 - 7 - 0 - 4 - 6 - 8 - 2 (AFTER MODIFICATION)
At the .01 significance level is it reasonable to conclude that the modification reduced the number of traffic accident?