Question

In Excel, create a forecast for periods 6-13 using the following method:

4 period weighted moving average. Weights: (0.63, 0.26, 0.08, 0.03)

Using the 4 period weighted moving average, the forecast for period 13 will be:

Period	Data
1	45
2	52
3	48
4	59
5	55
6	55
7	64
8	58
9	73
10	66
11	69
12	74

Answer 1

Last four periods are 9,10,11 and 12 with data values 73,66,69 and 74 respectively

We know that weighted moving average formula for forecast is given as

where xi are given data values and Wi are their respective weights, i.e. Weights: (0.63, 0.26, 0.08, 0.03)

Required forecast for 13 period is 70.89 or 71 (rounded to nearest integer)

In Excel, apply sum product function to calculate the weighted moving average for 13 period forecast.

=SUMPRODUCT(M10:M13, N10:N13)..................where M10:M13 is data value and N10:N13 are respective weights

= 70.89