A grocery store sells organic fruits for MYR20 each. The store recorded the following weekly sales data for the last ten weeks: Week 1 2 3 4 5 6 7 8 9 10 Sales 90 80 110 75 95 100 120 85 70 105 a. Calculate a 4-week weighted moving average forecast for each week from week 5 to week 11 using weights of 0.4, 0.3, 0.2, and 0.1 (largest weight is for most recent data). (3 marks) b. Calculate an exponentially smoothed forecast from week 1 to week 11 using a forecast for week 1 of 90 and an alpha of 0.5. (5 marks) c. Which method is more likely to have a better forecast performance? Provide a calculation to support your answer.