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Operations Research Models and Methods
 
Problems Section
Problems for Queueing Models
 - Interpret Results

The figure at the left shows a table built by the Queueing Add-In. The arrival and service rates are in units per hour. From the information given, answer the questions below.

Quantity
Value
Units
Arrival Rate when Empty
5
per hour
Service Rate/Channel
2
per hour
Number of Channels
2
 
Max. Number in System
***
 
Type
M/M/2/5
 
Mean Number in System
3.277
units
Mean Number in Queue
1.486
units
Mean Number in Service
1.791
units
Throughput Rate
3.582
units/hour
P(0)
0.046
 
P(1)
0.116
 
P(2)
0.145
 
P(3)
0.182
 
P(4)
0.227
 
P(5)
0.284
 
P(6)
0.000
 

a. Give the meaning of each the symbols M/M given in the “Type” line.

b. What proportion of the arriving customers are not served by this queueing station?

c. For those customers that are served, how long on the average is the time between when they enter the queue and when they leave the service?

d. What is the probability that an arriving customer will wait in the queue?

e. What is the efficiency of the servers?


  
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