Question

A company making tires for bikes is concerned about the exact width of its cyclocross tires. The company has a lower specification limit of 22.8 mm and an upper specification limit of 23.2 mm. The standard deviation is 0.15 mm and the mean is 23 mm. What is the process capability index for the process?

Answer 1

cpk = 0.444

Step-by-step explanation:

Cpk is the process capability index for the process, USL (23.2) and LSL(22.8) are upper and lower specification limits of the process , the mean (23), the standard deviation(0.15). So by applying the formula, we get

Cpk = minimum of [(23.2-23)/(3*0.15),(23-22.8)/(3*0.15)]

= 0.444