4-1. Sales of a particular product (in thousands of dollars) for the years 2009 through 2012 have been $48,000,$64,000, and $83,000, respectively. (a) What sales would you predict for 2013, using a simple four-year moving average? (b) What sales would you predict for 2013 , using a weighted moving average with weights of 0.50 for the immediate preceding year and 0.3,0.15, and 0.05 for the three years before that? In question 4-1, taking actual 2009 sales of $48,000 as the forecast for 2010 , what sales would you forecast for 2011, 2012, and 2013, using exponential smoothing and a weight on actual values of (a) 0.4 and (b) 0.8 ? In question 4-1, what sales would you forecast for 2013, using the simple regression (least squares) method