Lean Six Sigma Green Belt Certification Certified Six Sigma Green Belt 1

Question 1

What distinguishes common cause variation from special cause variation in a process?

Accepted Answer

Common cause variation is inherent and systemic to the process, while special cause variation stems from assignable, external factors

Answer

Common cause variation requires immediate corrective action, while special cause variation can be ignored

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Common cause variation is always larger in magnitude than special cause variation

Answer

Common cause variation only occurs in manufacturing processes, while special cause variation occurs in service processes

Question 2

In a simple linear regression model, what does the coefficient of determination (R²) represent?

Accepted Answer

The proportion of total variance in the response variable that is explained by the predictor variable

Answer

The slope of the best-fit regression line relating X to Y

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The p-value indicating whether the regression relationship is statistically significant

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The standard error of the residuals around the regression line

Question 3

What is the primary purpose of conducting a Gage Repeatability and Reproducibility (Gage R&R) study?

Accepted Answer

To quantify how much of the observed process variation is attributable to the measurement system itself

Answer

To calculate the process capability index (Cpk) for a critical-to-quality characteristic

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To identify which operators are performing below standard and require retraining

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To establish the upper and lower specification limits for a product characteristic

Question 4

Which of the following best describes a key deliverable of the Measure phase in DMAIC?

Accepted Answer

A baseline process capability or sigma level that quantifies current performance

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A prioritized list of verified root causes derived from hypothesis testing

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A set of implemented solutions validated through pilot runs

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A control plan with response procedures for out-of-control conditions

Question 5

In Design of Experiments (DOE), what is a 'main effect'?

Accepted Answer

The average change in the response variable when a single factor moves from its low level to its high level

Answer

The combined interaction effect when two or more factors are changed simultaneously

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The residual error remaining after all factor effects are accounted for in the model

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The center-point run used to detect curvature in a factorial experiment

Question 6

What is the primary purpose of a Pareto chart in a Six Sigma project?

Accepted Answer

To apply the 80/20 rule by identifying the vital few categories that account for the majority of defects or problems

Answer

To determine whether process output follows a normal distribution

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To track a quality metric over time and detect process shifts

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To display the relationship and correlation strength between two continuous variables