Number of backpacks sold in a store is recorded for four quarters during the past 5 years as follows:

Winter Spring Summer Fall 2015 65 61 52 124 2016 71 73 57 101 2017 85 65 64 99 2018 79 83 55 130 2019 70 66 57 132 a. Determine the seasonal factors. b. Develop a yearly forecasting model for the data given above by using weighted moving average with n=3, w1-15%, w2=30 %, w3-55%. c. Using part a and b, what is your forecasts for Spring 2020. d. Develop a yearly forecasting model for the data given above by using the trend line e. Using part a and d, what is your forecast for Fall 2020. f. Compare both methods using MAD and select the most appropriate.