Universitätsprofessor
Dr.-Ing. Bernd Hellingrath
Lehrstuhl für Wirtschaftsinformatik
und Logistik
Leonardo-Campus 3
48149 Münster
Tel. +49 251 83-38000
Fax +49 251 83-38009
Exercise Operations Management
Chapter 2 – Demand Forecasting (Part 2)
Please note: In general round off to two digits.
, 2
Exercise 4: Moving Average, Simple Exponential Smoothing
The RoboTec Inc. has not changed the marketing expenses for a well-established welding robot
since several periods. Hence, the demand for this robot is approximately at a constant level for
some time and fluctuates only slightly. A good forecasting method should be used in order to
further decrease inventory and back order costs as well as to remain a competitive price. The
historic data about demand quantities for the welding robot is provided by the marketing
director (we are in period 10):
Requested
Period t Number [Robot]
1 154
2 170
3 155
4 159
5 178
6 181
7 164
8 157
9 168
10 183
a) Illustrate the demand behavior.
180
160
140
Requested Number [Item]
120
100
80
60
40
20
0
0 1 2 3 4 5 6 7 8 9 10 11 12
Period
Dr.-Ing. Bernd Hellingrath
Lehrstuhl für Wirtschaftsinformatik
und Logistik
Leonardo-Campus 3
48149 Münster
Tel. +49 251 83-38000
Fax +49 251 83-38009
Exercise Operations Management
Chapter 2 – Demand Forecasting (Part 2)
Please note: In general round off to two digits.
, 2
Exercise 4: Moving Average, Simple Exponential Smoothing
The RoboTec Inc. has not changed the marketing expenses for a well-established welding robot
since several periods. Hence, the demand for this robot is approximately at a constant level for
some time and fluctuates only slightly. A good forecasting method should be used in order to
further decrease inventory and back order costs as well as to remain a competitive price. The
historic data about demand quantities for the welding robot is provided by the marketing
director (we are in period 10):
Requested
Period t Number [Robot]
1 154
2 170
3 155
4 159
5 178
6 181
7 164
8 157
9 168
10 183
a) Illustrate the demand behavior.
180
160
140
Requested Number [Item]
120
100
80
60
40
20
0
0 1 2 3 4 5 6 7 8 9 10 11 12
Period
