Quantitative Method (3)

The demand of a certain dehumidifier for the last six years is shown below:
Year 1 Demand 5200
Year 2 Demand 6500
Year 3 Demand 5000
Year 4 Demand 6800
Year 5 Demand 5600
Year 6 Demand 7000
a)Determine the forecast for year 7 using
i)Three-year moving average
ii)Exponential smoothing with α = 0.2 and initial forecast of 5500
iii)Trend projection method
b)Calculate the MADs for the three methods in part a) and hence identify which method gives the beast forecast.