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 10
IRREGULARITIES 2 6 4 8 6 6 8 2 5 5

a. Determine the c¯ , Sp, UCL and LCL for a c -chart with z = 2. (Leave no cells blank. Round up any negative LCL value to "0". Round your answers to 2 decimal places.)

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

multiple choice
Yes
No