Three-Year Moving Average

Data collected on the yearly registration for a seminar at GIPS are shown in the following table:

Year                    1 2 3 4 5 6 7 8 9 10 11
Registrations (000) 4 6 4 5 10 8 7 9 12 14 15

a) Develop a 3-year moving average to forecast registration from year 4 to year 12.

b) Estimate demands again for years 4 to 12 with a weighted moving average in which registration in the most recent year are given a weight of 2 and registration in the other 2 years are given a weight of 1.

c) Graph the original data and the two forecasts. Which of the two forecasting methods seems better?