Lean Six Sigma Green Belt Certification Study Guide 2026

The Analyze phase focuses on using data and analytical tools (such as fishbone diagrams, regression, and hypothesis testing) to identify and statistically verify the true root causes of the problem before moving to solutions.

The 10 to 30% range is a gray zone where acceptance depends on the importance of the application, the risk of measurement error, and the cost-benefit of improving the system.

In Lean Six Sigma, waste (Muda) refers to any activity that consumes resources but adds no value to the customer. Common categories of waste include defects, overproduction, waiting, non-utilized talent, transportation, inventory, motion, and extra processing. While recycling is an environmental practice, it is not typically categorized as a direct type of operational waste in the context of identifying non-value-adding activities within a process.

A Type II error (beta error) occurs when you fail to reject the null hypothesis even though it is actually false.

Voice of the Customer captures customer expectations and preferences to guide project priorities.

Poka-Yoke (Japanese for 'mistake-proofing') devices are designed to prevent errors from occurring or to detect them immediately so they cannot reach the next step.