Lean Six Sigma Yellow Belt Certification Lean Six Sigma Yellow Belt Certification 1 — Questions and Answers
Question 1: Which tool is commonly used to visually display the frequency distribution of defects or problems in a process?
- Control chart
- Histogram (Correct answer)
- Affinity diagram
- Scatter plot
Correct answer: Histogram
A histogram displays the frequency distribution of data, making it easy to see the shape, spread, and center of a dataset — useful for understanding process variation.
Question 2: In Lean Six Sigma, what does the term 'Kaizen' refer to?
- A Japanese term for defect elimination
- A method for calculating sigma levels
- A philosophy of continuous incremental improvement (Correct answer)
- A tool for mapping value streams
Correct answer: A philosophy of continuous incremental improvement
Kaizen is a Japanese philosophy meaning 'change for the better,' focused on making small, continuous improvements involving all employees rather than large one-time overhauls.
Question 3: Which of the following best describes a 'process capability index' (Cp)?
- A ratio comparing process spread to specification limits (Correct answer)
- The number of defects per million opportunities
- A chart tracking process output over time
- A measure of customer satisfaction
Correct answer: A ratio comparing process spread to specification limits
The Cp index measures how well a process fits within its specification limits by comparing the specification width to the process spread (6 sigma), indicating whether the process is capable of meeting requirements.
Question 4: What is the primary goal of the 'Control' phase in DMAIC?
- Identify potential root causes using a fishbone diagram
- Implement process improvements and pilot solutions
- Sustain gains and prevent the process from reverting to old behavior (Correct answer)
- Define the problem scope and project goals
Correct answer: Sustain gains and prevent the process from reverting to old behavior
The Control phase ensures that improvements made during the project are maintained long-term through control plans, monitoring systems, and standardized procedures to prevent backsliding.
Question 5: Which Lean waste category describes producing more output than what is currently needed by the customer?
- Waiting
- Overproduction (Correct answer)
- Motion
- Defects
Correct answer: Overproduction
Overproduction is considered the most serious of the eight Lean wastes because it generates inventory, consumes resources, and can mask other process problems.
Question 6: A team plots defect counts for each category in descending order with a cumulative percentage line. What tool are they using?
- Run chart
- Pareto chart (Correct answer)
- Control chart
- Cause-and-effect diagram
Correct answer: Pareto chart
A Pareto chart combines a bar chart (categories ranked by frequency) with a line showing cumulative percentage, helping teams apply the 80/20 rule to focus on the most significant problems first.
Lean Six Sigma Yellow Belt Certification Lean Six Sigma Yellow Belt Certification 1
Which tool is commonly used to visually display the frequency distribution of defects or problems in a process?