Studies on a machine that molds plastic water pipe indicate that when it is injecting 25.31 mm diameter pipe, the process standard deviation is 0.75 mm. The pipe has a specification of 25.31 mm plus or minus 2.45 mm. What is the process capability index (Cp)?
a, 1.089 b. 2.178 c. 3.267 d. 0.5444
