Lean Six Sigma Green Belt Measure Phase and Statistics Questions and Answers

Question 1

A Six Sigma team is analyzing the measurement system for a critical process characteristic. They conduct a study where multiple operators measure the same set of parts multiple times. The goal is to determine how much of the observed variation is due to the measurement equipment versus the people using it. What is this type of study called?

Accepted Answer

Gage Repeatability & Reproducibility (R&R) Study

Answer

A Gage R&R study is a specific type of Measurement System Analysis (MSA) that assesses two key components of measurement variation: Repeatability (variation from the measurement device) and Reproducibility (variation from different operators). This analysis is crucial in the Measure phase to ensure that the data collected is trustworthy before moving on to the Analyze phase.

Question 2

A project team has collected data on the time it takes to process a customer order. The data includes values like 3.45 days, 2.87 days, and 4.12 days. Which type of data has the team collected?

Accepted Answer

Continuous

Answer

Continuous data, also known as variable data, can take on any value within a given range and can be measured on an infinitely divisible scale. Measurements such as time, weight, length, and temperature are classic examples of continuous data. Attribute, nominal, and ordinal data are all types of discrete data, which are based on counts or categories.

Question 3

A process has an Upper Specification Limit (USL) of 65 cm and a Lower Specification Limit (LSL) of 55 cm. A statistical analysis reveals that the process has a Cp of 1.5 and a Cpk of 0.8. What can be concluded about this process?

Accepted Answer

The process is not centered between the specification limits.

Answer

Cp measures the potential capability, indicating if the process variation can fit within the specification limits. A Cp of 1.5 suggests the process spread is narrow enough. However, Cpk measures the actual capability by considering how centered the process is. A Cpk less than 1.0 (in this case, 0.8) indicates that the process mean is shifted towards one of the specification limits, making it not centered and likely producing defects.

Question 4

Which of the following is an essential component of a robust Data Collection Plan in the Measure Phase?

Accepted Answer

An operational definition of what is being measured.

Answer

A Data Collection Plan is a structured document created in the Measure phase to ensure data is collected consistently and is relevant to the project. An essential component is the operational definition, which provides a clear, precise description of the metric being measured, how it is measured, and by whom. This removes ambiguity and ensures all data collectors gather information in the same way. The other options are elements of later DMAIC phases or financial justifications.

Question 5

A Green Belt is preparing to collect data to establish a process baseline. To ensure the data is reliable and the measurement system is not introducing excessive variation, what activity should be performed FIRST?

Accepted Answer

Conduct a Measurement System Analysis (MSA).

Answer

Before extensive data collection for process analysis, it is critical to validate the measurement system. A Measurement System Analysis (MSA) determines if the measurement system's variation is acceptable. If the measurement system is unreliable, the data collected will be flawed, leading to incorrect conclusions in the Analyze phase. Calculating sigma, control charting, and brainstorming root causes all depend on having trustworthy data first.

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Certification Practice Test

Lean Six Sigma Green Belt Measure Phase and Statistics Questions and Answers