Sales of Volkswagen's popular Beetle have grown steadily at auto dealerships in Nevada during the past 5 years (see table below). :I Year Sales 1 450 2 495 3 520 4 570 5 580 a) Forecasted sales for year 6 using a 3year moving average is 556.66 sales (round your response to one decimal place). b) The MAD for a 3-year moving average based forecast is D sales (round your response to one decimal place). c) What is the MSE