Example Problem Solution


[Page 647]

The following example problem demonstrates a manual simulation using discrete probability distributions.

Problem Statement

Members of the Willow Creek Emergency Rescue Squad know from past experience that they will receive between zero and six emergency calls each night, according to the following discrete probability distribution:

Calls

Probability

.05

1

.12

2

.15

3

.25

4

.22

5

.15

6

.06

 

1.00


The rescue squad classifies each emergency call into one of three categories: minor, regular, or major emergency. The probability that a particular call will be each type of emergency is as follows :

Emergency Type

Probability

Minor

.30

Regular

.56

Major

.14

 

1.00


The type of emergency call determines the size of the crew sent in response. A minor emergency requires a two-person crew, a regular call requires a three-person crew, and a major emergency requires a five-person crew.

Simulate the emergency calls received by the rescue squad for 10 nights, compute the average number of each type of emergency call each night, and determine the maximum number of crew members that might be needed on any given night.

Solution

Step  1.
Develop Random Number Ranges for the Probability Distributions

Calls

Probability

Cumulative Probability

Random Number Range, r 1

.05

.05

15

1

.12

.17

617

2

.15

.32

1832

3

.25

.57

3357

4

.22

.79

5879

5

.15

.94

8094

6

.06

1.00

9599,00

 

1.00

   


[Page 648]

Emergency Type

Probability

Cumulative Probability

Random Number Range, r 2

Minor

.30

.30

130

Regular

.56

.86

3186

Major

.14

1.00

8799, 00

 

1.00

   

Step  2.
Set Up a Tabular Simulation

Use the second column of random numbers in Table 14.3:

Night

r 1

Number of Calls

r 2

Emergency Type

Crew Size

Total per Night

1

65

4

71

Regular

3

 
     

18

Minor

2

 
     

12

Minor

2

 
     

17

Minor

2

9

2

48

3

89

Major

5

 
     

18

Minor

2

 
     

83

Regular

3

10

3

08

1

90

Major

5

5

4

05

5

89

5

18

Minor

2

 
     

08

Minor

2

 
     

26

Minor

2

 
     

47

Regular

3

 
     

94

Major

5

14

6

06

1

72

Regular

3

3

7

62

4

47

Regular

3

 
     

68

Regular

3

 
     

60

Regular

3

 
     

88

Major

5

14

8

17

1

36

Regular

3

3

9

77

4

43

Regular

3

 
     

28

Minor

2

 
     

31

Regular

3

 
     

06

Minor

2

10

10

68

4

39

Regular

3

 
     

71

Regular

3

 
     

22

Minor

2

 
     

76

Regular

3

11


Step  3.
Compute Results

If all the calls came in at the same time, the maximum number of squad members required during any 1 night would be 14.




Introduction to Management Science
Introduction to Management Science (10th Edition)
ISBN: 0136064361
EAN: 2147483647
Year: 2006
Pages: 358

Similar book on Amazon

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net