A manufacturer embarking on a Six Sigma program sets the goal of having True Six Sigma capability for all processes by the end of the month. If their current process capability index on a key metric is less than 2.0 and the process capability ratio is 1.0, what must happen with the process standard deviation?
A) The process standard deviation must be doubled.
B) The process standard deviation must be reduced by a factor of six.
C) The process standard deviation must be cut in half.
D) The process tolerances should be doubled.

Question

Quizplus · Accepted Answer

The process capability index (Cpk) must be at least 2.0 for True Six Sigma capability. The process capability ratio (Cp/Cpk) of 1.0 indicates that the process is not centered, meaning that it is not meeting the customer's requirements. To achieve True Six Sigma capability, the process standard deviation must be reduced, which will increase the Cpk value. Cutting the process standard deviation in half (option C) would be the most effective way to achieve this, as it would double the Cpk value. Doubling the process standard deviation (option A) would decrease the Cpk value, while reducing the process standard deviation by a factor of six (option B) would likely be unrealistic and could lead to other problems. Doubling the process tolerances (option D) would have no impact on the process standard deviation or the Cpk value.

A Manufacturer Embarking on a Six Sigma Program Sets the Goal