SPC Fundamentals 1 — Questions and Answers
Question 1: What is the main purpose of Statistical Process Control (SPC)?
- Maximize machine downtime
- Eliminate all variability
- Monitor and control process variation (Correct answer)
- Reduce headcount
Correct answer: Monitor and control process variation
SPC is used to monitor and control a process to ensure it operates at its full potential to produce conforming product.
Question 2: What does a control chart indicate in SPC?
- Equipment maintenance needs
- Workforce productivity
- Process stability and variation (Correct answer)
- Customer preferences
Correct answer: Process stability and variation
Control charts show whether a process is in statistical control by detecting variation beyond normal limits.
Question 3: What is the term for variation caused by unpredictable events in a process?
- Common cause variation
- Special cause variation (Correct answer)
- Machine drift
- Tool wear
Correct answer: Special cause variation
Special cause variation refers to unexpected changes due to external or assignable causes.
Question 4: Which chart type is used for attribute data in SPC?
- X-bar chart
- R-chart
- P-chart (Correct answer)
- Histogram
Correct answer: P-chart
P-charts are used to monitor the proportion of defective items in a sample and are suitable for attribute data.
Question 5: What does it mean if all points fall within control limits on a control chart?
- Process is out of control
- Operator error present
- Process is stable and in control (Correct answer)
- Equipment needs repair
Correct answer: Process is stable and in control
If all points are within limits and show no pattern, the process is considered to be in control.
Question 6: Which SPC tool visually displays the frequency of data values?
- Scatter plot
- Pareto chart
- Histogram (Correct answer)
- Run chart
Correct answer: Histogram
A histogram is a graphical representation of data distribution used to visualize variation.
SPC Fundamentals 1
What is the main purpose of Statistical Process Control (SPC)?