Historical demand for a product is as follows:

DEMAND April May June July August September 60 55 75 60 80 75

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

b. Using single exponential smoothing with ␣ 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 2, and so on, while the Y axis is demand.

d. Calculate a forecast for October.