MR Data Analysis and Interpretation 3 — Questions and Answers
Question 1: An MR is analyzing customer satisfaction survey results using a Likert scale. Which measure of central tendency is most appropriate for ordinal data?
- Mean
- Median (Correct answer)
- Standard deviation
- Range
Correct answer: Median
The median is the most appropriate measure of central tendency for ordinal data because it preserves rank order without assuming equal intervals.
Question 2: When presenting QMS performance data to top management, which format best communicates trends over multiple reporting periods?
- A single bar chart showing current period only
- A line graph showing data across consecutive periods (Correct answer)
- A pie chart showing current period distribution
- A table of raw numbers without visualization
Correct answer: A line graph showing data across consecutive periods
A line graph across consecutive periods clearly displays trends, direction of change, and rate of improvement over time.
Question 3: Process data has a mean of 50 and standard deviation of 5. Upper specification limit is 62. What is the process sigma level?
- 1.2 sigma
- 2.0 sigma
- 2.4 sigma (Correct answer)
- 3.0 sigma
Correct answer: 2.4 sigma
The distance from mean to USL is 12 units; dividing by standard deviation (5) gives 2.4 sigma.
Question 4: Which type of data requires attributes control charts such as p-charts or c-charts?
- Continuous measurement data like temperature
- Count or proportion of nonconforming units (Correct answer)
- Normally distributed variable data
- Time-stamped process readings
Correct answer: Count or proportion of nonconforming units
Attribute control charts handle count data (defects per unit) or proportions (fraction defective), not continuous measurements.
Question 5: A Management Representative must determine if a new supplier's defect rate is statistically different from the previous supplier. Which analytical approach is appropriate?
- Visual comparison of bar charts
- Hypothesis testing using appropriate statistical tests (Correct answer)
- Calculating only the mean defect rate
- Reviewing only the most recent delivery
Correct answer: Hypothesis testing using appropriate statistical tests
Hypothesis testing provides a statistically rigorous method to determine if observed differences are significant or due to random variation.
Question 6: In ISO 9001 management review, the MR presents KPI data showing on-time delivery declined from 95% to 88%. Which additional data analysis would most add value?
- Recalculating the same metric using different units
- Stratifying the decline by customer, product line, or time period to find the root driver (Correct answer)
- Presenting only the annual average to smooth the data
- Removing outlier months from the calculation
Correct answer: Stratifying the decline by customer, product line, or time period to find the root driver
Stratification breaks aggregated data into subgroups to reveal which segment is driving the decline, enabling targeted corrective action.
Question 7: What is the primary purpose of establishing baseline data before implementing a process improvement?
- To satisfy regulatory documentation requirements only
- To provide a reference point for measuring the impact of the improvement (Correct answer)
- To delay implementation until more data is collected
- To identify who is responsible for current performance
Correct answer: To provide a reference point for measuring the impact of the improvement
Baseline data establishes a pre-improvement benchmark, enabling objective measurement of whether the change produced the intended effect.
MR Data Analysis and Interpretation 3
An MR is analyzing customer satisfaction survey results using a Likert scale.
Which measure of central tendency is most appropriate for ordinal data?