A shirt manufacturer buys cloth by the 100-yard roll from a supplier. For setting up a control chart to manage the irregularities (e.g., loose threads and tears), the following data were collected from a sample provided by the supplier.
Sample 1 2 3 4 5 6 7 8 9 1 0
Irregularities 3 5 2 6 5 4 6 3 4 5
a. Using these data, set up a c-chart with z 5 2.
b. Suppose the next five rolls from the supplier had three, two, five, three, and seven irregularities. Is the supplier process under control?
Solve the given numerical problem and illustrate step by step calculation.