One-pound coffee cans are filled by a machine, sealed, and then weighed by a local coffee store.

Question:

One-pound coffee cans are filled by a machine, sealed, and then weighed by a local coffee store. After adjusting for the weight of the can, any package that weighs less than 16 oz is cut out of the conveyor. The weights of 25 successive cans are shown in Table 5E.8. Set up a moving range control chart and a control chart for individuals. Estimate the mean and standard deviation of the amount of coffee packed in each can. Is it reasonable to assume that weight is normally distributed? If the process remains in statistical control at this level, what percentage of cans will be underfilled?