BE/B Eng Bachelor of Engineering Industrial Engineering 2 — Questions and Answers
Question 1: In Six Sigma methodology, the DMAIC improvement cycle stands for:
- Design, Measure, Analyze, Improve, Control
- Define, Measure, Analyze, Improve, Control (Correct answer)
- Define, Monitor, Assess, Integrate, Complete
- Design, Model, Analyze, Implement, Check
Correct answer: Define, Measure, Analyze, Improve, Control
DMAIC is the structured Six Sigma improvement framework: Define the problem, Measure the current process, Analyze root causes, Improve the process, and Control the gains.
Question 2: A process operating at Six Sigma quality level produces approximately how many defects per million opportunities (DPMO)?
- 3.4 (Correct answer)
- 66,807
- 233
- 6,210
Correct answer: 3.4
Six Sigma quality corresponds to 3.4 DPMO, based on a normal distribution shifted 1.5 sigma from the mean relative to specification limits.
Question 3: The process capability index Cp is calculated using which formula?
- (USL − LSL) / 6σ (Correct answer)
- (Mean − LSL) / 3σ
- (USL − Mean) / 3σ
- (USL + LSL) / (2 × Mean)
Correct answer: (USL − LSL) / 6σ
Cp = (USL − LSL) / 6σ compares the width of the specification (tolerance) range to the natural spread of the process (6 standard deviations), regardless of process centering.
Question 4: In statistical process control (SPC), a p-chart is used to monitor:
- The average value of a continuous quality characteristic within subgroups
- The range of measurements within each sample subgroup
- The proportion of nonconforming (defective) items in successive samples (Correct answer)
- The total number of defects per unit of product
Correct answer: The proportion of nonconforming (defective) items in successive samples
The p-chart tracks the fraction or proportion of nonconforming items in samples over time to detect shifts in the process defect rate.
Question 5: Acceptance sampling is a quality technique used primarily to:
- Control quality during active production by adjusting process parameters
- Inspect every single item in a shipment to guarantee 100% conformance
- Decide whether to accept or reject an entire lot based on inspection of a random sample (Correct answer)
- Train operators to reduce defect rates through skill development
Correct answer: Decide whether to accept or reject an entire lot based on inspection of a random sample
Acceptance sampling applies statistical decision rules to a random sample to accept or reject the entire lot, balancing inspection cost against the risk of accepting bad lots.
Question 6: In a Pareto analysis applied to quality improvement, the '80-20 rule' implies that:
- 80% of quality problems are caused by all factors equally
- Approximately 20% of defect types (vital few) account for roughly 80% of quality failures (Correct answer)
- 80% of products generate only 20% of total revenue
- Eliminating 20% of workers will reduce 80% of defects
Correct answer: Approximately 20% of defect types (vital few) account for roughly 80% of quality failures
Pareto analysis identifies the vital few causes (≈20%) that are responsible for the majority (≈80%) of problems, enabling focused improvement efforts.
Question 7: In Failure Mode and Effects Analysis (FMEA), the Risk Priority Number (RPN) is calculated as:
- Severity × Occurrence × Detection (Correct answer)
- Frequency × Impact × Probability
- Severity + Occurrence + Detection
- (Severity × Occurrence) / Detection
Correct answer: Severity × Occurrence × Detection
RPN = Severity × Occurrence × Detection, where each factor is rated 1–10; higher RPN values indicate failure modes that require priority corrective action.
BE/B Eng Bachelor of Engineering Industrial Engineering 2
In Six Sigma methodology, the DMAIC improvement cycle stands for: