MEM Operations Management 3 — Questions and Answers
Question 1: A hospital emergency department has an average arrival rate of 10 patients/hour and an average service rate of 12 patients/hour. Using M/M/1 queuing, what is the average time a patient spends in the system?
- 30 minutes (Correct answer)
- 20 minutes
- 10 minutes
- 60 minutes
Correct answer: 30 minutes
W = 1/(μ−λ) = 1/(12−10) = 0.5 hours = 30 minutes.
Question 2: Which supply chain risk mitigation strategy involves holding excess inventory at strategic locations to buffer against supply disruptions?
- Forward stocking (Correct answer)
- Postponement
- Cross-docking
- Vendor-managed inventory
Correct answer: Forward stocking
Forward stocking places buffer inventory closer to demand points to absorb upstream supply disruptions quickly.
Question 3: An operation has a cycle time of 4 minutes per unit and a shift of 480 minutes with 60 minutes of planned downtime. What is the takt time if customer demand is 100 units per shift?
- 4.2 minutes (Correct answer)
- 4.8 minutes
- 4.0 minutes
- 5.0 minutes
Correct answer: 4.2 minutes
Available time = 480 − 60 = 420 minutes; takt time = 420 / 100 = 4.2 minutes per unit.
Question 4: In the DMAIC framework used in Six Sigma projects, the 'Analyze' phase primarily focuses on which activity?
- Identifying root causes of defects (Correct answer)
- Establishing process baselines
- Implementing process changes
- Verifying financial savings
Correct answer: Identifying root causes of defects
The Analyze phase uses statistical tools to identify and verify the root causes driving process variation and defects.
Question 5: A manufacturer selects suppliers using a weighted-score model. Supplier A scores 80 on quality (weight 0.5), 70 on delivery (weight 0.3), and 90 on cost (weight 0.2). What is the total weighted score?
- 79 (Correct answer)
- 80
- 78
- 81
Correct answer: 79
Score = (80×0.5) + (70×0.3) + (90×0.2) = 40 + 21 + 18 = 79.
Question 6: Which forecasting method is most appropriate when a time series exhibits both trend and seasonal components?
- Holt-Winters exponential smoothing (Correct answer)
- Simple moving average
- Naive forecasting
- Linear regression alone
Correct answer: Holt-Winters exponential smoothing
Holt-Winters (triple exponential smoothing) explicitly models level, trend, and seasonal components simultaneously.
Question 7: In facility layout design, a product layout is most advantageous when which condition is met?
- High volume, low variety production (Correct answer)
- Low volume, high variety production
- Intermittent batch production
- Project-based one-off production
Correct answer: High volume, low variety production
Product (line) layouts are optimized for high-volume, standardized production where the sequence of operations is fixed.
MEM Operations Management 3
A hospital emergency department has an average arrival rate of 10 patients/hour and an average service rate of 12 patients/hour.
Using M/M/1 queuing, what is the average time a patient spends in the system?