4.

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.

Use the data table presented in Question 1 and double (trend-adjusted) exponential smoothing method to forecast sales for months 2 to 7, assuming A1 = 1443 and T1 = - 30 and set =0.9 and =0.4.

Month	Sales / Demand
1	1443
2	1358
3	1342
4	1298
5	1277
6	1183

The forecast sales for month 2 (F₂) is .

The forecast sales for month 3 (F₃) is .

The forecast sales for month 4 (F₄) is .

The forecast sales for month 5 (F₅) is .

The forecast sales for month 6 (F₆) is .

The forecast sales for month 7 (F₇) is .

Calculate the forecast errors for months 2 to 6, and then compute MAD and MAPE for those months for the double exponential smoothing forecast and compare them with those of simple exponential smoothing in Question 2(b). Based on your calculations, is simple or double exponential smoothing a better forecasting approach in this specific case?

The MAD of forecast errors for months 2 to 6 is .

The MAPE of forecast errors for months 2 to 6 is %.

Based on the calculations in Question 2 and this question, a better forecasting approach in this specific case is method.

[Note: please input either "simple exponential smoothing" or "double exponential smoothing".]