For Exercises 12.41 and 12.42, see page 636; and for 12.43 and 12.44, see page 638.
12.43 Worker safety.
safety
An investigation of the out-of-control signal seen in Figure 12.20 revealed that not only were there new hires that month, but new machinery was installed. The combination of relatively inexperienced employees and unfamiliarity with the new machinery resulted in an unusually high number of injuries. Remove the out-of-control observation from the data count series and recompute the chart control limits. Comment on control of the remaining counts.
12.43
, so use 0. The remaining points are in control.