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.

Using these data, set up a c-chart with z = 2.

Suppose the next five rolls from the supplier had three, two, five, three, and seven irregularities. Is the supplier process under control?

Sample 1 2 Irregularities 3 5 3 2 4 6 5 5 6 4 7 6 8 3 9 4 10 5