# Hw2 Slution

Topics: Forecasting, Harshad number, Mean absolute percentage error Pages: 4 (762 words) Published: March 6, 2013
Month
Sales
FMAMJJAS
20
0
2. a.

b. 1)
| | t| Y| tY| From Table 3–1 with n = 7, t = 28, t2 = 140| | | 1| 19| 19| |
| | 2| 18| 36| |
| | 3| 15| 45| |
| | 4| 20| 80| |
| | 5| 18| 90| |
| | 6| 22| 132| |
| | 7| 20| 140| |
| | 28| 132| 542| |
For Sept., t = 8, and Yt = 16.86 + .50(8) = 20.86 (000)

2)
Solutions (continued)
3)| | Month| Forecast =| F(old)| +| .20[Actual – F(old)]| | | April| 18.8=| 19| +| .20[18 – 19]| | | May| 18.04=| 18.8| +| .20[15 – 18.8]| | | June| 18.43=| 18.04| +| .20[20 – 18.04]| | | July| 18.34=| 18.43| +| .20[18 – 18.43]| | | August| 19.07=| 18.34| +| .20[22 – 18.34]| | | September| 19.26=| 19.07| +| .20[20 – 19.07]|

4)20
5).6 (20) + .3(22) + .1(18) = 20.4
c. Probably 5 month moving average because the data appear to vary around an average of about 19 [18.86].
d.Sales are reflective of demand (i.e., no stockouts or backorders occurred). 7.| a.| t| Y| t*Y| t2|
| 1| 220| 220| 1|
| 2| 245| 490| 4|
| 3| 280| 840| 9|
| 4| 275| 1,100| 16|
| 5| 300| 1,500| 25|
| 6| 310| 1,860| 36|
| 7| 350| 2,450| 49|
| 8| 360| 2,880| 64|
| 9| 400| 3,600| 81|
| 10| 380| 3,800| 100|
| 11| 420| 4,620| 121|
| 12| 450| 5,400| 144|
| 13| 460| 5,980| 169|
| 14| 475| 6,650| 196|
| 15| 500| 7,500| 225|
| 16| 510| 8,160| 256|
| 17| 525| 8,925| 289|
| 18| 541| 9,738| 324|
| 171| 7001| 75,713| 2109|

b.F = 208.444 + (19)(20) = 588.444
F = 208.444 + (19)(21) = 607.444
The forecasted demand for week 20 and 21 is 588.444 and 607.444...