Case 1 Mr. Analyst from Company XYZ is in charge of forecasting the company's quarterly sales for the next year. He gathered quarterly sales for the past five years and the data are shown below. Mr. Analyst started with the following forecasting models: moving average and Winter's exponential smoothing. 1. Forecast for the four quarters for this next year using the moving average model and Winters exponential smoothing method. Which method should Mr. Analyst use? Why? 2. Examine the residual autocorrelation of the mode you recommended to Mr. Analyst. Are you happy with the model? Explain. Date Sales 2000 Quarter 1 19350 2000 Quarter 2 21650 2000- Quarter 3 21780 2000-Quarter 4 25620 2001-Quarter 1 21040 2001-Quarter 2 20830 2001-Quarter 3 19780 2001-Quarter 4 22140 2002-Quarter 1 18030 2002-Quarter 2 19650 2002-Quarter 3 19820 2002-Quarter 4 23680 2003-Quarter 1 20060 2003-Quarter 2 21630 2003 Quarter 3 21520 2003 Quarter 4 25910 2004-Quarter 1 22180 2004 Quarter 2 23100 2004 Quarter 23350 2004 Quarter 4 27670 C Case 1 Mr. Analyst from Company XYZ is in charge of forecasting the company's quarterly sales for the next year. He gathered quarterly sales for the past five years and the data are shown below. Mr. Analyst started with the following forecasting models: moving average and Winter's exponential smoothing. 1. Forecast for the four quarters for this next year using the moving average model and Winters exponential smoothing method. Which method should Mr. Analyst use? Why? 2. Examine the residual autocorrelation of the mode you recommended to Mr. Analyst. Are you happy with the model? Explain. Date Sales 2000 Quarter 1 19350 2000 Quarter 2 21650 2000- Quarter 3 21780 2000-Quarter 4 25620 2001-Quarter 1 21040 2001-Quarter 2 20830 2001-Quarter 3 19780 2001-Quarter 4 22140 2002-Quarter 1 18030 2002-Quarter 2 19650 2002-Quarter 3 19820 2002-Quarter 4 23680 2003-Quarter 1 20060 2003-Quarter 2 21630 2003 Quarter 3 21520 2003 Quarter 4 25910 2004-Quarter 1 22180 2004 Quarter 2 23100 2004 Quarter 23350 2004 Quarter 4 27670 C