SPC Data Collection & Interpretation 1 — Questions and Answers
Question 1: Which type of data is used when counting defects in a product?
- Variable data
- Nominal data
- Attribute data (Correct answer)
- Interval data
Correct answer: Attribute data
Attribute data involves counts such as the number of defects or defective items.
Question 2: What is the main benefit of using random sampling in SPC?
- It eliminates all variation
- It increases defect rates
- It reduces sampling bias (Correct answer)
- It requires fewer tools
Correct answer: It reduces sampling bias
Random sampling reduces bias and provides a representative snapshot of the process.
Question 3: Which chart is best for monitoring continuous measurement data?
- P-chart
- X-bar chart (Correct answer)
- Run chart
- Fishbone diagram
Correct answer: X-bar chart
X-bar charts are designed to track the average of variable (measurement) data in subgroups.
Question 4: What does the term 'bias' refer to in measurement systems?
- Measurement repeatability
- Measurement reproducibility
- Systematic error from true value (Correct answer)
- Natural variability
Correct answer: Systematic error from true value
Bias is the difference between the observed average measurement and the true value.
Question 5: Which factor impacts the reliability of data interpretation the most?
- Chart colors
- Auditor experience
- Measurement system quality (Correct answer)
- Sample storage
Correct answer: Measurement system quality
The accuracy and precision of the measurement system directly impact how reliable data interpretation is.
Question 6: What is the purpose of a Measurement Systems Analysis (MSA)?
- To document operator attendance
- To calibrate machine output
- To assess measurement system performance (Correct answer)
- To track downtime
Correct answer: To assess measurement system performance
MSA evaluates the accuracy, precision, and stability of a measurement system used in data collection.
SPC Data Collection & Interpretation 1
Which type of data is used when counting defects in a product?