please explain what functions to use for |et| et^2 and |et|/At

a (6 pts) Use a 2-year moving average to forecast the number of surgeries from year 3 to year 6. b (9 pts) Compute MAD, MSE, and MAPE. Demand for heart transplant surgery at Washington General Hospital has increased steadily in the past few years, as shown below. The director of medical services wants to choose a forecast method to predict the demand in year 6