5.3. For the packing nut data of Table 4.1, find the central line and control limits for a p chart, analyzing as past data. Comment on control. In March samples of 50 packing nuts gave the following counts of np¼d: 0, 0, 4, 0, 1, 4, 5, 0, 0, 7, 0, 0, 0, 0, 0, 0, 2, 3. Make an appropriate chart and comment.

Such charts were of great value to the company involved in this case.