Question

If the forecast for September is based on the data series below and the forecast for September is 19, then which forecasting method was used?

January	February	March	April	May	June	July	August
18	21	20	22	21	20	21	17

Moving average (n = 2)

Moving average (n = 3)

Averaging

Last value

Answer 1

Question: If the forecast for September is based on the data series below and the forecast for September is 19, then which forecasting method was used?

Answer: Moving Average (n = 2)

Explanation:

1. Moving Average is given by:

Moving Average = (A1 + A2 + A3 + ... + An) / n

Here for:

n = 2

September Forecast = (17 + 21) / 2 = 19

n = 3

September Forecast = (17 + 21 + 20) = 19.33

2. Averaging

September Forecast = (17 + 21 + 20 + 21 + 22 + 20 + 21 + 18) / 8 = 20

3. Last Value

Last Values is given by:

Forecast Ft = Actual At-1

Therefore:

September Forecast = August Actual = 17

Conclusion: Moving Average Forecast with n = 2 provides the September forecast = 19