Lean Six Sigma Green Belt Analyze Phase Tools Questions and Answers — Questions and Answers
Question 1: A Six Sigma team is analyzing customer complaints for a software application. They create a chart that displays the complaint categories in descending order of frequency, and also shows the cumulative percentage. This allows them to visually identify the few categories that account for the majority of the problems. Which tool is the team using?
- Control Chart
- Pareto Chart (Correct answer)
- Scatter Plot
- Fishbone Diagram
Correct answer: Pareto Chart
A Pareto Chart is used to graphically summarize and display the relative importance of the differences between groups of data. It is based on the Pareto Principle, or 80/20 rule, which states that for many events, roughly 80% of the effects come from 20% of the causes. This chart helps teams focus their efforts on the 'vital few' causes that have the largest impact on the problem.
Question 2: A project team wants to understand the relationship between two continuous variables: advertising spend (X) and product sales (Y). They suspect that as advertising spend increases, sales also increase. Which statistical tool in the Analyze phase would be most appropriate to quantify the strength and direction of this relationship?
- Analysis of Variance (ANOVA)
- Chi-Square Test
- Regression Analysis (Correct answer)
- 5 Whys
Correct answer: Regression Analysis
Regression Analysis is a statistical method used to model the relationship between a dependent variable (Y) and one or more independent variables (X). It is ideal for this scenario as it can determine if a statistically significant relationship exists between advertising spend and sales, and it can quantify that relationship.
Question 3: In the Analyze phase, a team is using Failure Mode and Effects Analysis (FMEA) to proactively identify and address potential problems in a new process. They have identified a potential failure mode and rated its Severity as 8, its Occurrence as 3, and its Detection as 6. What is the Risk Priority Number (RPN) for this failure mode?
- 17
- 24
- 48
- 144 (Correct answer)
Correct answer: 144
The Risk Priority Number (RPN) in an FMEA is calculated by multiplying the rankings for Severity (S), Occurrence (O), and Detection (D). In this case, RPN = Severity × Occurrence × Detection = 8 × 3 × 6 = 144. A higher RPN indicates a higher-risk failure mode that should be prioritized for improvement actions.
Question 4: A Green Belt is leading a team to find the fundamental cause of a recurring machine breakdown. The initial problem is 'The conveyor belt stopped'. The team proceeds by asking 'Why did it stop?', then 'Why did that happen?', and so on, to drill down to the most basic cause. Which root cause analysis tool are they employing?
- Brainstorming
- Affinity Diagram
- 5 Whys (Correct answer)
- Hypothesis Testing
Correct answer: 5 Whys
The 5 Whys is an iterative interrogative technique used to explore the cause-and-effect relationships underlying a particular problem. By repeatedly asking the question "Why?" (five is a general rule of thumb), the team can peel away layers of symptoms and uncover the root cause of a defect or problem.
Question 5: Which of the following activities is a primary goal of the Analyze phase in a DMAIC project?
- To implement and pilot the proposed solution.
- To develop a detailed data collection plan.
- To use data and statistical methods to verify the root causes of a problem. (Correct answer)
- To create a control plan to sustain the gains from the project.
Correct answer: To use data and statistical methods to verify the root causes of a problem.
The core purpose of the Analyze phase is to take the data collected in the Measure phase and use it to identify, validate, and prioritize the root causes of the problem. This involves using various graphical and statistical tools to move from potential causes to proven root causes before jumping to solutions.
Question 6: A team is investigating if there is a statistically significant difference in the average call handling time between two different call centers. They have collected sample data from both centers. To formally test the assumption that the means are different, what statistical method should they use?
- Process Capability Analysis (Cp/Cpk)
- Gage R&R Study
- Hypothesis Testing (e.g., t-test) (Correct answer)
- Failure Mode and Effects Analysis (FMEA)
Correct answer: Hypothesis Testing (e.g., t-test)
Hypothesis testing is a formal procedure for using sample data to evaluate a claim about a population. In this scenario, a hypothesis test, such as a 2-sample t-test, is the appropriate tool to determine if the observed difference in average call handling times between the two centers is statistically significant or likely due to random chance.
Lean Six Sigma Green Belt Analyze Phase Tools Questions and Answers
A Six Sigma team is analyzing customer complaints for a software application.
They create a chart that displays the complaint categories in descending order of frequency, and also shows the cumulative percentage.
This allows them to visually identify the few categories that account for the majority of the problems.
Which tool is the team using?