For Super Soil,the lower specification fill weight is 35.0 pounds and the upper specification fill weight is 35.5 pounds.The filling process has a standard deviation of 0.4 pounds and the process is in control.Find the process capability index.
A)0.208
B)1.25
C)88.75
D)0.1

Question

Quizplus · Accepted Answer

The process capability index (Cpk) is calculated as the minimum of the upper and lower process capability indices (Cpu and Cpl). In this case, the lower specification limit (LSL) is 35.0 pounds and the upper specification limit (USL) is 35.5 pounds. The process mean is not given, but we can assume that it is centered between the LSL and USL, or 35.25 pounds. The process standard deviation is 0.4 pounds.The upper process capability index (Cpu) is calculated as:Cpu = (USL - process mean) / (3 * process standard deviation)Cpu = (35.5 - 35.25) / (3 * 0.4)Cpu = 0.167The lower process capability index (Cpl) is calculated as:Cpl = (process mean - LSL) / (3 * process standard deviation)Cpl = (35.25 - 35.0) / (3 * 0.4)Cpl = 0.208The process capability index (Cpk) is the minimum of Cpu and Cpl, which in this case is 0.167. Therefore, the correct answer is A.

For Super Soil,the Lower Specification Fill Weight Is 35