Question 2: Problem solving (10 Marks)

The historical data below is on the monthly demand on a product in number of units:

Period	1	2	3	4	5	6
Month	Jan.	Feb.	Mar.	Apr.	May	Jun.
Demand	50	55	42	68	68	88

1. Compute the Demand forecast for the month of July using the moving average of order 3. Compute the whole MA series (show computation for July). (2 Marks)
2. Compute the Demand forecast for the month of July using the weighted moving average of order 3, the weights from the most recent month are: 60%, 30%, and 10%. Compute the whole WMA series (show computation for July). (2 Marks)
3. Compute the Demand forecast for the month of July using the exponential smoothing with = 0.3, assuming that F₁ = 50 units (show computation for July). (2 Marks)
4. Calculate the tracking signal TS for exponential smoothing and plot it (show computation for March). Based on the plot, is the ES forecast in control? Explain why. (4 Marks)