The specification limits for a product are 8 cm and 10 cm.A process that produces the product has a mean of 9.5 cm and a standard deviation of 0.2 cm.What is the process capability,Cpk?
A) 3.33
B) 1.67
C) 0.83
D) 2.50
E) None of the choices are correct.

Question

Quizplus · Accepted Answer

Cpk is calculated using the formula:

Cpk = min((USL - µ) / 3σ, (µ - LSL) / 3σ)

where USL is the Upper Specification Limit (10 cm), LSL is the Lower Specification Limit (8 cm), µ is the process mean (9.5 cm), and σ is the process standard deviation (0.2 cm).

Plugging in the values:

Cpk = min((10 - 9.5) / (3 * 0.2), (9.5 - 8) / (3 * 0.2)) = min(2.5, 0.83) = 0.83

Therefore, the process capability Cpk is 0.83, which is answer choice C.

The Specification Limits for a Product Are 8 Cm and 10