(POM for Windows or Excel OM) The following table represents quarterly data on the number of four-wheel drive sport-utility vehicles sold by a local Toyota dealer during the past three years.

SUV Sales (2019-Q₁ 2020-Q₄)

Year	Quarter	Time	Units Sold
2018	1	1	23
	2	2	25
	3	3	36
	4	4	31
2019	1	5	26
	2	6	28
	3	7	48
	4	8	36
2020	1	9	31
	2	10	42
	3	11	53
	4	12	43

For each of the following forecasting methods report their respective MAD and MAPE. Summarize all your findings in a table. Please, answer all letters below; A, B, C, D.

1. Use regression analysis to fit a linear trend model to the data set (regression over time). Interpret your findings. What are the forecasts for the four quarters of 2020? Report and interpret the coefficient of determination.

2. Use a simple exponential smoothing model to forecast sales for the first quarter of 2020. Use POM or Excel/OM, by setting the smoothing coefficient at = 0.25 and use the actual sales in the first quarter of 2019 as forecast, to start your forecasting process, (i.e. F₁ = 23)

3. Use the multiplicative decomposition model to forecast sales for the next four quarters of 2020. Report and interpret the significance of seasonal indexes (i.e. what do the seasonal indexes mean).

4. Which model provides the best overall forecast for this data? Use MAPE as the criterion.