Professor
Dr.-Ing. Bernd Hellingrath
Chair for Information Systems and
Supply Chain Management
Leonardo-Campus 3
48149 Münster
Tel. +49 251 83-38000
Fax +49 251 83-38009
Tutorial Operations Management
Chapter 2 – Demand Forecast (Part 2)
Solutions
Please note: In general round off to two digits.
Exercise 4: Moving Average, Simple Exponential Smoothing
a)
200
180
160
Requested Amount [Item]
140
120
100
80
60
40
20
0
0 2 4 6 8 10 12
Period
, 2
b)1
To compare the MSEs, we calculate the MSE for periods 5 to 10:
MSET=2=259.04
MSET=3=223.81
MSET=4=171.18 (smallest MSE Use T=4 for the forecast)
Forecast valur for period 11 with T=4:
t
1
ŷ t 1 y
T t T 1
10
1 1 1
ŷ11
4 10 4 1
y (y 7 y8 y9 y10 ) (164 157 168 183) 168
4 4
Forecasts for periods 5 to 10:
Requested
Periode Forecast
Amount [Items]
t (T=4)
5 178 159.50
6 181 165.50
7 164 168.25
8 157 170.50
9 168 170.00
10 183 167.50
1 The tables to calculate the MSEs can be found in the appendix of this document.
Dr.-Ing. Bernd Hellingrath
Chair for Information Systems and
Supply Chain Management
Leonardo-Campus 3
48149 Münster
Tel. +49 251 83-38000
Fax +49 251 83-38009
Tutorial Operations Management
Chapter 2 – Demand Forecast (Part 2)
Solutions
Please note: In general round off to two digits.
Exercise 4: Moving Average, Simple Exponential Smoothing
a)
200
180
160
Requested Amount [Item]
140
120
100
80
60
40
20
0
0 2 4 6 8 10 12
Period
, 2
b)1
To compare the MSEs, we calculate the MSE for periods 5 to 10:
MSET=2=259.04
MSET=3=223.81
MSET=4=171.18 (smallest MSE Use T=4 for the forecast)
Forecast valur for period 11 with T=4:
t
1
ŷ t 1 y
T t T 1
10
1 1 1
ŷ11
4 10 4 1
y (y 7 y8 y9 y10 ) (164 157 168 183) 168
4 4
Forecasts for periods 5 to 10:
Requested
Periode Forecast
Amount [Items]
t (T=4)
5 178 159.50
6 181 165.50
7 164 168.25
8 157 170.50
9 168 170.00
10 183 167.50
1 The tables to calculate the MSEs can be found in the appendix of this document.
