Assignment:
Emergency calls to Detroit, Michigan 911 system, for the past 24 weeks are as follows
week - calls week - calls week - calls
1 50 9 35 17 55
2 35 10 20 18 40
3 25 11 15 19 35
4 40 12 40 20 60
5 45 13 55 21 75
6 35 14 35 22 50
7 20 15 25 23 40
8 30 16 55 24 65
(a) Compute the exponentially smoothed forecast of calls for each week. Assume an initial forecast of 50 calls in the first week and use σ = 0.1. What is the forecast for the 25th week?
(b) Reforecast each period using σ = 0.6
(c) Actual calls during the 25th week were 85. Which smoothing constant provides a superior forecast?