Lean Six Sigma Green Belt Certification Lean Six Sigma Green Belt Knowledge 1

Question 1

Which statistical measure describes the spread of data around the mean by calculating the average of squared deviations?

Accepted Answer

Variance

Answer

Variance is the average of the squared deviations from the mean. Standard deviation is simply the square root of variance and is more commonly reported, but variance is the direct measure of squared deviations.

Question 2

In the DMAIC framework, during which phase would a team use a Fishbone (Ishikawa) diagram to identify root causes?

Accepted Answer

Analyze

Answer

The Fishbone diagram is a root cause analysis tool used in the Analyze phase to systematically explore potential causes of a defect or problem across categories such as Man, Machine, Method, Material, Measurement, and Environment.

Question 3

What does Process Capability Index (Cpk) measure?

Accepted Answer

How well a process fits within specification limits, accounting for process centering

Answer

Cpk measures how well a process performs relative to its specification limits while also accounting for whether the process mean is centered. A Cpk of 1.33 or higher is generally considered acceptable.

Question 4

Which of the following best describes 'Poka-Yoke' in Lean manufacturing?

Accepted Answer

A mistake-proofing mechanism that prevents defects from occurring or reaching the next step

Answer

Poka-Yoke (mistake-proofing) involves designing processes or tools so that errors are impossible or immediately detected, preventing defects from being passed downstream.

Question 5

A control chart shows several consecutive points trending upward on one side of the center line. This pattern is called:

Accepted Answer

A run rule violation indicating a special cause

Answer

A run rule violation — such as seven or more consecutive points trending in one direction — signals a special cause of variation. Even if all points remain within control limits, a non-random pattern indicates the process has shifted.

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification Lean Six Sigma Green Belt Knowledge 1