Part B- Problems (24 points) Q1) A specialized electronic store sells products ranging from laptops to digital cameras. One of their high selling products is 22mm lens for digital cameras. Demand for 22 mm lens in the last 8 years are as follows: Year Demand 2015 300 2016 380 2017 290 2018 310 2019 325 2020 322 The supply chain manager thinks that demand stable over the years and is considering two methods to forecast the demand for 2021, i.e., (i) 3 years moving average (ii) 3 years weighted moving average with weights (6,3,1) and (iii) exponential smoothing with smoothing constant a=0.4 to forecast the demand. For exponential smoothing methods, he would start this method with forecast for year 2015 F2015=300 for 2015. a) What are the forecasts for 2018, 2019, 2020 and 2021 according to 3 years moving average? (2 points) b) What are the forecasts for 2018, 2019, 2020 and 2021 according to 3 years weighted moving average? (2 points) c) What are the forecasts for 2018, 2019, 2020 and 2021 according to exponential smoothing? (2 points) d) Compare the forecasts in (a), (b) and (c) using MAD and indicate which forecasting method is the most accurate. (4 points)