I found it is in under control. It stays between limits but I do not understand that imperfections are so much. how is it under control? the production has to be stoped. Could you clear my confusion but not the problem?

6-37, A paper mill uses a control chart to mon- itor the imperfection in finished rolls of paper. Production output is inspected for 20 days, and the resulting data are shown here. Use these data to set up a control chart for nonconformities per roll of paper. Does the process appear to be in statistical control? What center line and control limits would you recommend for controlling current production? Total Number Number of of Rolls Imper- Produced fections Day Day 1 2 3 4 5 6 7 8 9 10 Total Number Number of of Rolls Imper- Produced fections 18 12 18 14 24 20 22 18 22 15 22 12 20 11 20 15 20 12 20 10 11 12 13 14 15 16 17 18 19 18 18 18 20 20 20 24 24 22 21 18 14 9 10 14 13 16 18 20 17 20 Show transcribed image text