Chapter 15

Here are the gasoline sales time series data:

Week Sales (1000s of gallons)

 1 17 2 21 3 19 4 23 5 18 6 16 7 20 8 18 9 22

1. 10 20
2. 11 15
3. 12 22

a.(10 points) To calculate forecasts use a weight of 1/2 for the most recent observation, 1/3 for the second most recent, and 1/6 for the third most recent and compute a 3-week weighted moving average for the time series. Calculate the MSE. b. (10 points) Calculate forecasts by using the 3-period unweighted moving averages and the corresponding MSE. c. (10 points) Calculate forecasts by using exponential smoothing with =0.35 Calculate the MSE. d) (5 points) Which method do you prefer and why?