Studies on a bottle-filling machine indicate that it fills bottles to a mean of 16 ounces with a standard deviation of 0.10 ounces. What is the process specification, assuming the Cpk index of 1?
A) lower spec = 0.1 ounces and upper spec = 1 ounce
B) lower spec = 14.3 ounces and upper spec = 17.7 ounces
C) lower spec = 12.0 ounces and upper spec = 21.4 ounces
D) lower spec = 15.7 ounces and upper spec = 16.3 ounces
E) There is insufficient information to determine the process specification.

Question

Quizplus · Accepted Answer

The Cpk index of 1 indicates that the process mean is centered between the specification limits, which are 3 standard deviations away from the mean on either side. Therefore, the lower spec is 16 - 3(0.10) = 15.7 ounces and the upper spec is 16 + 3(0.10) = 16.3 ounces.

Studies on a Bottle-Filling Machine Indicate That It Fills Bottles