Question: Emergency calls to the city of Durham NC for the past 24 weeks are shown:
Week 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Calls 50 35 25 40 45 35 20 30 35 20 15 40 55 35 25 55 55 40 35 0 75 50 40 65
(a) Use a 2-month moving average on all the data and plot the averages and calls.
(b) Use a 3-month weighted moving average and add the 3-month plot to graph created for (a). Use weight of 4 for most recent period, and 2 for each subsequent period.
(c) Compute forecastsfor each month using exponentialsmoothing, with an initial forecast = 50. Use a = 0.3 and a = 0.7 and plot the results on the same chart.
d) Compute the forecast using TREND (Regression) model.
(e) Using MAD for all models, which yields a more accurate forecast?