Plastic strips that are used in a sensitive
electronic device are manufactured to a maximum
specification of 305.70mm and a minimum
specification of 304.55mm.

If the strips are less
that the minimum specification they are
scrapped if greater than the maximum
specification they are reworked. The part
dimensions are normally distributed with a
population mean of 305.20mm and a standard
deviation of 0.25mm. What percentage of the
product is scrap What percentage is rework How
can the process be centred to eliminate all but
0.1 of the scrap What is the rework percentage