Squirt Inc. has decided to use a p-Chart with 2-sigma control limits to monitor the proportion of defective industrial belts produced by their production process. The quality control manager randomly samples 450

450 industrial belts at 16

16 successively selected time periods and counts the number of defective industrial belts in the sample.

Sample Defects

1 7

2 12

3 10

4 11

5 14

6 7

7 10

8 8

9 10

10 9

11 10

12 13

13 13

14 11

15 13

16 14

Step2of8:What value ofzshould be used to construct the control chart?