A major objective of Six Sigma quality-control programs is to better meet customers’ needs. One place companies have applied Six Sigma is to order delivery times. They have directed efforts at reducing both the mean (average) time to delivery and the variance or standard deviation (dispersion) of the delivery times. Customers want to get their products sooner, as reflected in the mean. But they also want assurance that the product will arrive when promised. This requires delivery schedules to have little random variance.

Consider the following experience with the implementation of Six Sigma at a major manufacturing company:

Order Delivery ………. Times (Days)

Before Six Sigma ………. After Six Sigma

28 ………………………… 16

10 ………………………… 21

13 ………………………… 12

7 ………………………… 7

24 ………………………… 16

21 ………………………… 4

22 ………………………… 5

24 ………………………… 16

28 ………………………… 11

43………………………… 2

Compute the mean and standard deviation of order-delivery time before and after implementation of Six Sigma. From a customer’s perspective, how would you view the results of this application of Six Sigma?

Exhibit 9-13 Quality Cost Area 20X4 Cost 20X6 Cost 107 12.4% 132 15.2% 368 42.5% 607 70.1 % 259 29,9% 866 1. Prevention cost 2. Appraisal cost 3. Internal failure cost 45 Percentage of total quality cost 3.3% 124 Percentage of total quality cost 503 36.9% 672 49.3% 691 50.7% Percentage of total quality cost Total internal quality cost 1 2 +3) Percentage of total quality cost 4. Extemal failure cost Percentage of total quality cost Total quality cost Total product cost 1,363 22,168 23,462