Six Sigma Black Belt Flashcards

In a full factorial 2³ experiment with 3 factors at 2 levels each, how many experimental runs are required (without replication)?

Answer: 8

A 2³ full factorial design requires 2³ = 8 experimental runs to test all combinations of 3 factors at 2 levels.

Which FMEA severity rating criterion would typically be assigned to a failure mode that could cause injury without warning?

Answer: Rating 9-10 (very high/hazardous)

A severity rating of 9-10 is reserved for failure modes that involve safety hazards or regulatory non-compliance, especially those occurring without warning.

What is the key distinction between 'common cause' and 'special cause' variation?

Answer: Common cause variation is random and systemic; special cause variation is assignable to a specific factor

Common cause (random) variation is inherent to the process and requires system-level changes to reduce, while special cause variation stems from identifiable, assignable factors.

A Black Belt wants to test whether a process median has changed after an improvement. The data is non-normal and small-sample. Which test is most appropriate?

Answer: Wilcoxon signed-rank test

The Wilcoxon signed-rank test is the non-parametric equivalent of the one-sample t-test and is used when data is non-normal or the sample is small.

In a multiple linear regression model, what does multicollinearity refer to?

Answer: High correlation among two or more predictor variables

Multicollinearity occurs when predictor variables are highly correlated with each other, inflating standard errors and making individual coefficient estimates unreliable.

Which Six Sigma concept describes the practice of verifying that gains from a project are sustained 6-12 months after project closure?

Answer: Sustaining the gains / benefit realization

Sustaining the gains (benefit realization) involves monitoring key metrics and control plan adherence long after the project is handed off to ensure improvements hold.

When using a Pugh Concept Selection Matrix, what serves as the baseline against which all alternatives are compared?

Answer: The current process or datum

In a Pugh matrix, the current design or a reference concept (datum) is used as the baseline; alternatives are rated as better (+), worse (-), or same (S) relative to it.