A shirt manufacturer buys cloth by the 100 –yard roll from a supplier. For setting up a control chart to manage the irregularities (i.e. loose threats and tears), the following data were collected from a 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
Using these data, set up a c-chart with z = 2.
Suppose the next five rolls from the supplier had 3, 2, 5, 3, and 7 irregularities. Is the supplier’s process under control?