The dean of a school of business is forecasting total student enrollment for this year (2019)'s summer session classes based on the following historical data: TOTAL ENROLLMENT YEAR 2015 2016 2017 2018 y 2,000 2,200 2,800 3,000 a) What is this year's forecast using a three-year simple moving average? b) What is this year's forecast using a three-year weighted moving average with weights of 0.5, 0.3, and 0.2? c) What is this year's forecast using exponential smoothing with alpha=0.4, if year 2017's smoothed forecast was 2,600? d) What is the slope (b) of the least squares trend line for these data? e) What is the Y-intercept (a) of the least squares trend line for these data? f) What is this year's forecast using the least squares trend line for these data?