To make a decision on whether or not to switch to a different shippingcompany, 18 random samples of 50 deliveries each were collected and the number of late deliveries out of the respective 50 deliveries was counted. The results are shown below.

Sample Late Deliveries

1 7

2 4

3 4

4 7

5 3

6 4

7 4

8 6

9 2

10 3

11 4

12 2

13 6

14 8

15 4

16 3

17 8

18 8

What is the centerline used in constructing a P-chart? Round to 4 decimal