BHC produces bags of cement. The stated weight for a bag of cement is 100 lb. Customers will accept an occasional bag weighing as little as 96 lb., as long as the average weight is at least 100 lb. At the same time, BHC doesn't want to give away cement, so it has set an upper tolerance limit of 104 lb. The current filling process has an actual process mean of 101 lb. and a standard deviation of 0.65 lb.
a. Calculate the process capability index for BHC. In this example, why should we use the process capability index rather than the process capability ratio to assess capability?
b. Can you think of any reason BHC might want a process mean higher than the target value?