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 froma sample provided by the supplier.
Sample: 1 2 3 4 5 6 7 8 9 10
Irregularities: 3 5 2 6 5 4 6 3 4 5
(a) Using these data, set up a c-chart with z = 2.
(b) Suppose the next five rolls from the supplier had three, two, five, three, and seven irregularitiies. Is the supplier process under control?