Historical demand for a product is as follows:

Demand

April ............. 60

May ............. 55

June ............. 75

July ............. 60

August ............. 80

September ............. 75

a. Using a simple four- month moving average, calculate a forecast for October.

b. Using single exponential smoothing with α = 0.2 and a September forecast = 65, calculate a forecast for October.

c. Using simple linear regression, calculate the trend line for the historical data. Say the X axis is April = 1, May 5 2, and so on, while the Y axis is demand.

d. Calculate a forecast for October using your regression formula.