back in the early 20th century the tolerance of the weight o

back in the early 20th century, the tolerance of the weight of a dime at the U.S. Mint was 2.500 grams +/- 0.092 grams. AN inventor has developed a coin press by which raw sheet metal is cut and stamped into coins. When testing the machine and measuring its results, the Mint finds that the resulting coins weigh, on average, 2.509 grams, with a standard deviation of .016 grams.

A) what is the lower and upper specification limit? (round to 3 decimal places)

B) What is the process capability index? (round to 3 decimal places)

Solution

a)

lower : 2.500 - 0.092 = 2.408

upper = 2.500 + 0.092 = 2.592

b)

Process capability = (2.592 - 2.408) / 6*0.016 = 1.917