[60 MARKS] SECTION B Answer ALL questions. QUESTION 3 (20 Marks) In order to compare the accuracy of two forecasting methods used by PGX Ltd to forecast the monthly sales of a popular product, an operations analyst obtained the actual sales data as well as the forecasts prepared by the operations department. The table below shows the actual sales and forecasts the 12 months of the financial year ended 31 December 2020 MONTH ACTUAL SALES FORECAST METHOD A METHOD B January 78 86 86 February 60 March 80 78 75 Apri 80 75 75 May 78 85 June 82 86 84 July 88 August 75 76 78 September 68 74 70 October 80 79 November 79 December 88 90 89 56 50 82 85 89 83 83 83 REQUIRED 3.1 Calculate the mean absolute deviation (MAD) of forecasting method A and method B. (10 marks) 3.2 Calculate the mean squared error (MSE) of forecasting method A and method B. (8 marks) 3.3 Based on 31 and 32 above, which of the two methods should PGX Lid choose for the purpose (2 marks) of forecasting the product and why