Case 1

A local Municipal Council at Sepang thinks that adding traffic signal countdown timer helps to reduce the accidents at high-risk intersections within Cyberjaya area. Hence, the traffic department agreed to conduct an experiment to verify the claim. If the claim is true, then the traffic signal countdown timer will be installed in all intersections in Cyberjaya. 12 intersections were selected randomly. The number of accidents during a five-month period before and after the modifications were recorded in the Excel sheet named Traffic. Shall the traffic signal countdown timer be installed?

Intersection	Before modification	After modification
1	10	2
2	8	8
3	5	3
4	7	7
5	4	0
6	9	6
7	7	7
8	5	3
9	6	7
10	7	4
11	6	2
12	3	1