Quarterly demand for dishwashers at a white goods retailer is as shown. After obtaining initial estimates for level, trend, and seasonal factors, forecast quarterly demand for year 5 using Winter’s model with α = 0.10, β = 0.10, and γ = 0.10. Evaluate the MAD, MAPE,

MSE, bias, and TS for the forecast. Can you find values of α, β, γ that result in a lower MAD or MSE?