In order to develop a p control chart, the following information is obtained from four different samples, each of sample size 1000, of items produced by a process:

SAMPLE PROPORTION DEFECTIVE FOUND IN THE SAM1PLE

First 0.005

Second 0.004

Third 0.003

Fourth 0.004

Based on these information, what is the centerline for the p control chart?

a. 0.016 b. 0.004 c. 0.001 d. Not enough information given to answer this question