Consider the data set shown in Table 18.5.5, summarizing recent numbers of errors in batches of 500 invoices
a. Find the percentage, p, for each batch.
b. Find the average percentage, p.
c. Find the center line for the percentage chart.
d. Find the control limits for the percentage chart.
e. Draw the percentage chart.
f. Comment on what you see in the percentage chart. In particular, is this process in control? How do you know?
g. Write a paragraph, as if to your supervisor, summarizing the situation and defending the action you feel is appropriate.
