Accurate typesetting is crucial to the production of high-quality newspapers. The editor of the Morristown Daily Tribune, a weekly publication with circulation of 27,000, has instituted a process for monitoring the performance of typesetters. Each week 100 paragraphs of the paper are randomly sampled and read for accuracy.

The number of paragraphs with errors is recorded in the table below for each of the last 30 weeks.

a. Construct a p-chart for the process.

b. Is the process under statistical control? Explain.

c. Should the control limits of part a be used to moni- tor future process output? Explain.

d. Suggest two methods that could be used to facilitate the diagnosis of causes of process variation.