Test for mean numbers of accidents before and after modifications
A number of minor automobile accidents occur at various high-risk intersections in Teton County despite traffic lights. The Traffic Department claims that a modification in the sort of light will reduce these accidents. The county commissioners have agreed to a planned experiment. Eight intersections were chosen at random, and the lights at those intersections were modified. The numbers of minor accidents during a six-month period before and after the modifications were:
|
Â
|
Number of Accidents
|
|
A
|
B
|
C
|
D
|
E
|
F
|
G
|
H
|
|
Before modification
|
5
|
7
|
6
|
4
|
8
|
9
|
8
|
10
|
|
After modification
|
3
|
7
|
7
|
0
|
4
|
6
|
8
|
2
|
At the .01 significance level is it reasonable to finish that the modification reduced the number of traffic accidents?