The following data represents the average “delivery speed” to fulfill customer’s orders in a hypothetical organization. In period 10, changes were made on the fulfillment process, as a result of an improvement Six Sigma initiative. Period→ 1 2 3 4 5 6 7 8 9 10 Delivery Speed (days) 5 6 8 4 6 7 6 6 7 8 Period→ 11 12 13 14 15 16 17 18 19 20 Delivery Speed (days) 6 4 5 6 5 4 8 4 7 4 2. Explain if the change made in Period 10 was sound. 3.What is your forecast of delivery-speed in Period 21. You have to choose a model (consider at least three models and using the MAD explain which is the best.)