A product had a demand history (in 000s) by quarters over a two year period, as follows: 2020 Demand 2021 Demand 1 98 1 74 2 90 2 61 3 87 3 58 4 80 4 50 (a) Make a time plot and a seasonal plot of the demand history and comment on the characteristics of this time series. [20%] (b) Based on your analysis in part (a), apply a suitable forecasting approach to predict the quarterly demand for 2022. Explain all the steps and the assumptions that you make in your calculations (e.g. values for smoothing coefficients and/or initial values for intercept and/or slope levels). [50%] Using the forecasts for 2020 and 2021 in the table below, calculate the average forecast error, the mean absolute deviation (MAD) and the mean absolute percentage error (MAPE) based on forecasts and actual demand starting from year 2020, quarter 1 through to year 2021, quarter 4. Using the same metrics, calculate also the accuracy of the forecasts obtained in part (b) from year 2020, quarter 1 to year 2021, quarter 4 Compare, interpret and comment on the results. 2020 Forecast 2021 Forecast 1 97 1 88 2 96 2 87 3 93 87 4 91 84 [30%] O 3 4 A product had a demand history (in 000s) by quarters over a two year period, as follows: 2020 Demand 2021 Demand 1 98 1 74 2 90 2 61 3 87 3 58 4 80 4 50 (a) Make a time plot and a seasonal plot of the demand history and comment on the characteristics of this time series. [20%] (b) Based on your analysis in part (a), apply a suitable forecasting approach to predict the quarterly demand for 2022. Explain all the steps and the assumptions that you make in your calculations (e.g. values for smoothing coefficients and/or initial values for intercept and/or slope levels). [50%] Using the forecasts for 2020 and 2021 in the table below, calculate the average forecast error, the mean absolute deviation (MAD) and the mean absolute percentage error (MAPE) based on forecasts and actual demand starting from year 2020, quarter 1 through to year 2021, quarter 4. Using the same metrics, calculate also the accuracy of the forecasts obtained in part (b) from year 2020, quarter 1 to year 2021, quarter 4 Compare, interpret and comment on the results. 2020 Forecast 2021 Forecast 1 97 1 88 2 96 2 87 3 93 87 4 91 84 [30%] O 3 4