Studies on a Machine That Molds Plastic Water Pipe Indicate

Multiple Choice

Studies on a machine that molds plastic water pipe indicate that when it is injecting 1-inch-diameter pipe, the process standard deviation is 0.05 inches. The 1-inch pipe has a specification of 1 inch plus or minus 0.10 inch. What is the process capability index ( C_pk) if the long-run process mean is 1 inch?

A) 0.50
B) 0.67
C) 1.00
D) 2.00
E) 2.20