Webster Chemical Company produces tubes of mastic. Currently management is concerned that tubes are coming out that
Question:
Webster Chemical Company produces tubes of mastic. Currently management is concerned that tubes are coming out that are not properly capped and sealed. If this situation worsens, it could cause numerous complaints from customers who could choose to buy the equivalent product from the competition. The tubes are packed in boxes of 144 units. Twenty (20) complete boxes were inspected to verify whether the tubes were leaking or not. The inspection result is shown in the following table:
sample | pipe with leak | Proportion of tubes with leaking | sample | pipe with leak | Proportion of tubes with leaking |
1 | 3 | 0.0208 | 11 | 2 | 0.0139 |
2 | 5 | 0.0347 | 12 | 6 | 0.0417 |
3 | 3 | 0.0208 | 13 | 5 | 0.0347 |
4 | 4 | 0.0278 | 14 | 1 | 0.0069 |
5 | 2 | 0.0139 | 15 | 5 | 0.0347 |
6 | 4 | 0.0278 | 16 | 0 | 0.0000 |
7 | 2 | 0.0139 | 17 | 2 | 0.0139 |
8 | 6 | 0.0417 | 18 | 6 | 0.0417 |
9 | 4 | 0.0278 | 19 | 2 | 0.0139 |
10 | 9 | 0.0625 | 20 | 1 | 0.0069 |
Calculate the control limits for this process and assess whether Webster Chemical's capping and sealing process is in statistical control.