Question: A courier company is analyzing the effectiveness of its package handling system. The average number of packages per customer is 3.35, and the courier recorded 5 lost packages for 6500 customers in one month.
a. What is the ppm Defective for this process?
b. Assuming a mean shift of 1.5 sigma, the Sigma level for this process is approximately 5. If projects have an average improvement rate of 60% annually, how many years will it take the courier to achieve Six Sigma quality?