# mathematics

12. For the demand data in Problem 11, develop a seasonally adjusted forecast for year 4. (Use a linear trend line model to develop a forecast estimate for year 4.) Which forecast model do you perceive to be more accurate: the exponential smoothing model from Problem 11 or the seasonally adjusted forecast?
13. Develop a seasonally adjusted forecast for the demand data for fertilizer found in Problem 3. Then use a linear trend line model to compute a forecast estimate for demand in year 4.
14. Monaghan’s Pizza delivery service has randomly selected 8 weekdays during the past month and recorded orders for pizza at four different time periods per day: Day
Time Period 1 2 3 4 5 6 7 8 10:00 A . M .–3:00 P . M . 62 49 53 35 43 48 56 43 3:00 P . M .–7:00 P . M . 73 55 81 77 60 66 85 70 7:00 P . M .–11:00 P . M . 42 38 45 50 29 37 35 44 11:00 P . M .–12:00 A . M . 35 40 36 39 26 25 36 31 Develop a seasonally adjusted forecasting model for daily pizza demand and forecast demand for each of the time periods for a single upcoming day. 15. The Cat Creek Mining Company mines and ships coal. It has experienced the following demand for coal during the past 8 years: Year Coal Sales (tons) 1 4,260 2 4,510 3 4,050 4 3,720 5 3,900 6 3,470 7 2,890 8 3,100
Develop an adjusted exponential smoothing model ( a = .30, b = .20) and a linear trend line model and compare the forecast accuracy of the two by using MAD. Indicate which forecast seems to be more accurate.