Toyota Motors observes from the sales data that sales of Hybrid G has been decreasing over the last year. As mentioned earlier, this is due to introduction of a new hybrid model by Honda at the beginning of 2017.Toyota Motors wants to incorporate this decreasing trend into its forecasts. You have learned that the double exponential smoothing method accounts for such trends in the data.

a.Use the double (trend-adjusted) exponential smoothing method to forecast sales for months 2 to 13, assuming S₁ = 1,243 and T₁ = -30 and set =0.7 and =0.4.

b.Compute MAD and MAPE for months 2 through 12 for the double exponential smoothing forecast and compare them with those of simple exponential smoothing in problem 2(b). Based on your calculations, is single or double exponential smoothing a better approach in this specific case?Why?