Sales of Volkswagen's popular Beetle have grown steadily at auto dealerships in Nevada during the past 5 years (see table below). Sales D Year 1 455 2 495 3 516 4 555 595 a) Forecasted sales for year 6 using the trend projection (linear regression) method are sales (round your response to one decimal place) b) The MAD for a linear regression forecast is c) The MSE for the linear regression forecast is sales (round your response to one decimal place) sales (round your response to one decimal place)