Problem:
A company making smart phone cases is concerned about the exact length of their cases. The company has a lower specification limit of 12.75 cm and an upper specification limit of 13.25 cm. The standard deviation is 0.25 cm and the mean is 13 cm. The company now wants to reduce its defect probability and run a "Six Sigma Process".
To what level would they have to reduce the standard deviation in the process to meet this target?