SCM 300 Exam 2 Davila Questions with Correct Answers (Grade
A+)
Question 1: Goal of waiting line management
Answer: Balance the cost paid by the customers (time) with the cost paid by the company (money paid to
maintain the system)
Question 2: Parts of a waiting line system
Answer: 1. Input Source - This is the population of people that might want service 2. Waiting Line - The
area in which customers wait for service 3. Service Facility - The area in which customers actually receive
service
Question 3: 4 Managerial Considerations in Queues
Answer: 1) Customers - How many are there? How quickly are they arriving? 2) The Waiting Lines - What
types of lines? How many lines? 3) Employees - Who's working in the system? How many? Skill level and
speed? 4) Service Facilities - How effective and efficient is the process? Tools?
Question 4: Queue
Answer: Line
Question 5: Channel
Answer: Line; here it often refers to the number of lines available at each step
Question 6: Phase
Answer: A single step in a process
Question 7: Infinite population of customers
Answer: The number of possible customers that may come into the store is very high (or unlimited). When a
customer enters the system, the odds of another entering the system are not impacted in any significant
manner.
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, Question 8: Finite population of customers
Answer: The number of customers is limited. Example: If you have a bus company that has 10 busses, then
your company's repair shop has a finite population of 10 busses. If 1 bus is in the shop only 9 others are left
in the population. The odds of a 2nd bus entering the system decline.
Question 9: Arrival (λ) rates: define and calculate
Answer: Number of customers arriving / unit of time
Question 10: Service (μ) rates: define and calculate
Answer: Number of customers helped / unit of time
Question 11: Service utilization factor (ρ)
Answer: Percentage of time worker is busy. ρ=λ/μ
Question 12: Average number of customers in the line (nl)
Answer: nl = ρ[ λ / (μ-λ) ]
Question 13: Average amount of time a customer waits in the line (tl)
Answer: tl = ρ[ 1 / (μ-λ) ]
Question 14: Average number of customers in the system (ns)
Answer: ns = λ / (μ-λ)
Question 15: Average amount of time a customer spends in the system (ts)
Answer: 1 / (μ-λ)
Question 16: Probability there are "n" customers in the system (Pn)
Answer: P(n) = (1-ρ)ρ^n
Question 17: Probability the System is Empty (P0)
Answer: P(0) = 1-ρ
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A+)
Question 1: Goal of waiting line management
Answer: Balance the cost paid by the customers (time) with the cost paid by the company (money paid to
maintain the system)
Question 2: Parts of a waiting line system
Answer: 1. Input Source - This is the population of people that might want service 2. Waiting Line - The
area in which customers wait for service 3. Service Facility - The area in which customers actually receive
service
Question 3: 4 Managerial Considerations in Queues
Answer: 1) Customers - How many are there? How quickly are they arriving? 2) The Waiting Lines - What
types of lines? How many lines? 3) Employees - Who's working in the system? How many? Skill level and
speed? 4) Service Facilities - How effective and efficient is the process? Tools?
Question 4: Queue
Answer: Line
Question 5: Channel
Answer: Line; here it often refers to the number of lines available at each step
Question 6: Phase
Answer: A single step in a process
Question 7: Infinite population of customers
Answer: The number of possible customers that may come into the store is very high (or unlimited). When a
customer enters the system, the odds of another entering the system are not impacted in any significant
manner.
Page 1
, Question 8: Finite population of customers
Answer: The number of customers is limited. Example: If you have a bus company that has 10 busses, then
your company's repair shop has a finite population of 10 busses. If 1 bus is in the shop only 9 others are left
in the population. The odds of a 2nd bus entering the system decline.
Question 9: Arrival (λ) rates: define and calculate
Answer: Number of customers arriving / unit of time
Question 10: Service (μ) rates: define and calculate
Answer: Number of customers helped / unit of time
Question 11: Service utilization factor (ρ)
Answer: Percentage of time worker is busy. ρ=λ/μ
Question 12: Average number of customers in the line (nl)
Answer: nl = ρ[ λ / (μ-λ) ]
Question 13: Average amount of time a customer waits in the line (tl)
Answer: tl = ρ[ 1 / (μ-λ) ]
Question 14: Average number of customers in the system (ns)
Answer: ns = λ / (μ-λ)
Question 15: Average amount of time a customer spends in the system (ts)
Answer: 1 / (μ-λ)
Question 16: Probability there are "n" customers in the system (Pn)
Answer: P(n) = (1-ρ)ρ^n
Question 17: Probability the System is Empty (P0)
Answer: P(0) = 1-ρ
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