Using the data set below: (total of 5 marks) a. Calculate the three-period simple moving average forecast for month 4. (show the details of your calculations) (2 marks) b. Calculate the three-period weighted moving average forecast for month 4 using weights of 0.2, 0.3, and 0.5 from the earliest period to the latest period, respectively. (show the details of your calculations) (2 marks) c. Which forecast is more accurate and why is it more accurate? (1 mark) Month Demand 1 120 2 100 3 150 4 180