Sales of Volkswagen's popular Beetle have grown steadily at auto dealerships in Nevada during the past 5 years (see table below) Year Sales 1 450 502 2345 520 563 580 a) Forecasted sales for year 6 using a 3-year moving average is 554.3 sales (round your response to one decimal place). by The MAD for a 3-year moving average based forecast is sales (round your response to one decimal place). c) The MSE for a 3-year moving average based forecast is sales (round your response to the nearest whole number).