Free Lean Six Sigma Green Belt Knowledge Questions and Answers — Questions and Answers

Question 1: The "Funnel Effect" is the practice of narrowing the project team's attention to only one issue.

False (Correct answer)
True

Correct answer: False

The 'Funnel Effect' in Lean Six Sigma refers to the process of starting with a broad problem statement and progressively narrowing its scope to a specific, measurable, and manageable project. It's about defining a clear project scope, not necessarily restricting the team's attention to 'only one' issue in a limiting sense. The statement implies a restrictive focus that doesn't fully capture the concept.

Question 2: When assessing a data set's dispersion, average moving range is the preferable statistic above standard deviation.

False (Correct answer)
True

Correct answer: False

Standard deviation is generally the preferred and more robust statistic for measuring the dispersion or spread of a data set. While the average moving range can be used, especially in control charts for smaller subgroups, it is an estimate of variability and is less precise than the standard deviation, which directly calculates the average distance of data points from the mean. Therefore, standard deviation is typically considered superior for assessing overall dispersion.

Question 3: Is it true that the client specifies the standard deviations lines above and below the process data on control charts rather than the data's variation?

False (Correct answer)
True

Correct answer: False

The control limits on a control chart (typically set at +/- 3 standard deviations from the mean) are calculated based on the inherent variation of the process data itself, not specified by the client. These limits reflect the expected natural variation of the process. While clients might specify desired performance targets or specification limits, these are distinct from the statistically derived control limits used to monitor process stability.

Question 4: By employing the same measuring tool or the same measuring procedure to measure the exact same characteristic of the same part or object, what is meant by repeatability? (Also called the "within" variation)

False
True (Correct answer)

Correct answer: True

Repeatability, in Measurement System Analysis (MSA), specifically refers to the variation observed when the same operator uses the same measuring device to measure the same characteristic on the same part multiple times. It quantifies the inherent variability of the measurement device itself. This is often referred to as 'within' variation because it measures the consistency of a single operator and device.

Question 5: What does the C&E in a fishbone diagram stand for?

Cost and effort
Customer and employee
Cause and effect (Correct answer)
None of the above

Correct answer: Cause and effect

A fishbone diagram, also known as an Ishikawa diagram, is a visual tool used in Lean Six Sigma for root cause analysis. The 'C&E' stands for 'Cause and Effect,' as the diagram systematically categorizes potential causes (the 'bones') that contribute to a specific problem or effect (the 'head' of the fish). It helps teams brainstorm and identify underlying reasons for issues.

Question 6: Which of the following is not a typical way to identify waste?

Recycling (Correct answer)
Time
Processing
Motion

Correct answer: Recycling

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.

Question 7: The format and functionality of Minitab worksheets are exactly the same as those of an Excel worksheet.

False (Correct answer)
True

Correct answer: False

While both Minitab and Excel use a spreadsheet-like interface, their primary purposes and functionalities differ significantly. Excel is a general-purpose spreadsheet program for data organization, calculations, and basic charting. Minitab, on the other hand, is specialized statistical software designed for advanced statistical analysis, quality improvement, and Lean Six Sigma applications, offering specific tools and outputs not found in Excel.

Question 8: What else is the term "Poka-Yoke" known as?

Muda
Mistake proofing or errors to avoid (Correct answer)
The first step in 5S
Hoshin kanri

Correct answer: Mistake proofing or errors to avoid

Poka-Yoke is a Japanese term meaning 'mistake-proofing' or 'inadvertent error prevention.' It refers to designing processes or products in such a way that errors are either impossible to make or immediately obvious when they occur. The goal is to eliminate defects by preventing human errors at the source, rather than relying on inspection to catch them later.

Question 9: The "Rs" in Gauge R&R stand for repeatability and reproducibility in relation to MSAs.

False
True (Correct answer)

Correct answer: True

In Measurement System Analysis (MSA), Gauge R&R is a study used to assess the amount of variation in a measurement system. The 'R&R' specifically stands for Repeatability and Reproducibility. Repeatability measures the variation when the same operator measures the same part multiple times, while Reproducibility measures the variation when different operators measure the same part using the same gauge.

Question 10: The runs of your data collection for measurement system analysis should ideally be randomized.

False
True (Correct answer)

Correct answer: True

Randomization is a critical principle in experimental design, including Measurement System Analysis (MSA). Randomizing the order of measurements helps to minimize the impact of uncontrolled variables, such as operator fatigue, environmental changes, or tool wear, on the results. This ensures that any observed variation is truly due to the measurement system itself rather than extraneous factors, leading to more accurate and reliable data.

Question 11: This kind of information is frequently used in visual inspections to quantify problems with acceptance criteria.

Continuous data
Attribute data (Correct answer)
Does not really matter that I know they type of data
None of the above

Correct answer: Attribute data

Attribute data, also known as discrete data, is typically used in visual inspections where items are classified into categories, such as 'pass/fail,' 'conforming/non-conforming,' or counting defects. Unlike continuous data, which can be measured on a scale, attribute data involves counting occurrences or classifying observations based on acceptance criteria. This makes it suitable for quick, qualitative assessments in many inspection processes.

Question 12: Which chart should be analyzed first when analyzing an X-bar and Range chart? X-bar or Range charts are used.

Range chart (Correct answer)
X-Bar chart
Both
None of the above

Correct answer: Range chart

When analyzing X-bar and Range charts, the Range chart (or R chart) must be analyzed first. This is because the Range chart monitors the process variation or spread, and if the variation is not in statistical control, the X-bar chart (which monitors the process average) cannot be reliably interpreted. Ensuring the process variation is stable is a prerequisite for assessing the stability of the process average.

Question 13: In process mapping, box plots are an effective technique for revealing hidden factories.

False (Correct answer)
True

Correct answer: False

This statement is false. Box plots are graphical tools used to display the distribution of a dataset, showing its median, quartiles, and potential outliers. While useful for understanding data spread and central tendency, they are not designed for revealing 'hidden factories,' which refer to non-value-added activities or rework loops. Techniques like process mapping and value stream mapping are typically used to identify these hidden inefficiencies.

Question 14: What kind of control charts can I use when I have attribute data?

I-MR charts
X-Bar S charts
U or P charts (Correct answer)
None of the above

Correct answer: U or P charts

U or P charts are the appropriate control charts for attribute data. Attribute data involves counts of discrete events, such as the number of defects or defective units. P charts monitor the proportion of defective items, while U charts monitor the number of defects per unit, making them suitable for analyzing attribute data in a process.

Question 15: If you were the patient undergoing surgery, you would want the surgeon to have a low alpha risk. This would give you a high level of confidence that any defects would be found and corrected before you, the patient, received the procedure.

False
True (Correct answer)

Correct answer: True

This statement is true. Alpha risk (Type I error) is the probability of incorrectly rejecting a true null hypothesis. If the null hypothesis is framed as 'a defect exists,' then a low alpha risk means there's a low probability of incorrectly concluding 'no defect' when a defect actually exists. This ensures a high level of confidence that any defects will be found and corrected, which is paramount for patient safety.

Question 16: What is a C&E matrix used for primarily?

To find the hidden factory
To create a process map
To test for correlation
To use the knowledge of the group to determine the critical few (x’s) (Correct answer)

Correct answer: To use the knowledge of the group to determine the critical few (x’s)

A Cause & Effect (C&E) matrix, also known as an X-Y matrix, is primarily used to prioritize potential input variables (X's) based on their impact on critical output variables (Y's). It leverages the collective knowledge and experience of a team to systematically score and rank the X's, helping to identify the 'critical few' factors that have the most significant influence on the process output.

Free Lean Six Sigma Green Belt Knowledge Questions and Answers

The "Funnel Effect" is the practice of narrowing the project team's attention to only one issue.