Free Lean Six Sigma Green Belt Assessment Questions and Answers — Questions and Answers
Question 1: There is a ____ if the correlation coefficient is between 0.5 and 1.
- Positive correlation (Correct answer)
- Negative correlation
- No correlation
- Negative & Positive correlation
Correct answer: Positive correlation
A correlation coefficient (r) measures the strength and direction of a linear relationship between two variables. If the coefficient is between 0.5 and 1, it indicates a positive correlation. This means that as one variable increases, the other variable also tends to increase, and the relationship is considered strong.
Question 2: What is the most accurate way to define a hypothesis test?
- A tool for dissecting the data
- A tool for deciding if Statistical Significance exists between data samples (Correct answer)
- A tool for breaking up the problem in smaller parts
- A tool for brainstorming problems
Correct answer: A tool for deciding if Statistical Significance exists between data samples
A hypothesis test is a statistical method used to determine if there is sufficient evidence in a sample to draw conclusions about a population. Its most accurate definition is a tool for deciding if statistical significance exists between data samples, helping to ascertain whether observed differences or relationships are likely real or due to random chance.
Question 3: Which hypothesis test, however utilized when the data set is non-normal, is comparable to the one sample t-test?
- Kruskal-Wallis
- Mann-Whitney
- 1- sample sign (Correct answer)
- Friedman
Correct answer: 1- sample sign
The 1-sample t-test is a parametric test used for comparing a sample mean to a hypothesized population mean when data is normally distributed. When the data set is non-normal, the 1-sample sign test is its non-parametric equivalent. This test compares the median of a single sample to a hypothesized value without assuming a normal distribution.
Question 4: Who is regularly referred to as the "Father of quality control"?
- Dennis Edwards
- W. Edwards Deming (Correct answer)
- W. Frederick Deming
- F. Deming Edwards
Correct answer: W. Edwards Deming
W. Edwards Deming is widely regarded as the 'Father of Quality Control.' His pioneering work in statistical process control and management philosophy, particularly his 14 Points for Management, significantly influenced the global quality movement and helped revolutionize industrial practices, especially in post-war Japan.
Question 5: An example of a typical linear regression equation is
- 3.4 = DPMO
- Yield = 100%
- Y = a + bx (Correct answer)
- all of the above
Correct answer: Y = a + bx
The equation Y = a + bx is a typical representation of a simple linear regression equation. In this model, Y is the dependent variable, X is the independent variable, 'a' represents the Y-intercept (the value of Y when X is 0), and 'b' represents the slope of the line (the change in Y for a one-unit change in X).
Question 6: Which of the following is NOT a COMMON CAUSE VARIATION in a process?
- Regular daily changes in average outside temperature that effect ice-cream sales
- Serious workplace accidents that cause a shutdown for more than 2 hours (Correct answer)
- The number of cars that pass a drive-through fast-food restaurant per hour during the hours 12pm – 1pm each day
- Changes in the moods of customers every day that effect ticket sales
Correct answer: Serious workplace accidents that cause a shutdown for more than 2 hours
Common cause variation refers to the natural, inherent, and predictable fluctuations within a stable process. A serious workplace accident causing a shutdown for more than 2 hours is an unusual, non-routine event that is not part of the process's normal operation. Therefore, it represents a special cause variation, which is assignable and indicates the process is out of control.
Question 7: Which of the following tasks exemplifies non-value addition?
- Inspection
- Setup
- Rework (Correct answer)
- Packing
Correct answer: Rework
Rework is a classic example of a non-value-added activity, also known as waste (Muda) in Lean methodology. It involves repeating work that was not done correctly the first time, consuming resources and time without adding new value for the customer. While inspection, setup, and packing can sometimes be non-value-added, rework is almost universally considered pure waste.
Question 8: What does the term "waste" mean in Japanese?
- Muda (Correct answer)
- Mura
- Mode
- Muri
Correct answer: Muda
In Japanese, the term 'Muda' refers to waste, specifically any activity that consumes resources without adding value from the customer's perspective. It is one of the three types of waste (Muda, Mura, Muri) identified in the Toyota Production System, forming a core concept of Lean manufacturing.
Question 9: Which of the following is NOT a measure of a process's central tendency or position?
- Mean
- Mode
- Median
- Inter Quartile Range (Correct answer)
Correct answer: Inter Quartile Range
Measures of central tendency describe the typical or central value of a dataset, such as the Mean, Mode, and Median. The Inter Quartile Range (IQR), however, is a measure of statistical dispersion or spread. It quantifies the range within which the middle 50% of the data lies, indicating variability rather than central position.
Question 10: What is the numerically ranked middle value in a set of data?
- Median (Correct answer)
- Mode
- Variance
- Mean
Correct answer: Median
The median is defined as the numerically ranked middle value in a set of data. To find it, the data points are first arranged in ascending or descending order. If there is an odd number of data points, the median is the single middle value; if there is an even number, it is the average of the two middle values.
Question 11: A control chart is built by a Lean Six Sigma Green Belt practitioner to show the process mean and its tolerances. What does UCL represent in such a chart?
- Upper Cycle Limit
- Upper Cycle Length
- Upper Control Length
- Upper Control Limit (Correct answer)
Correct answer: Upper Control Limit
In a control chart, UCL stands for Upper Control Limit. Control limits are statistically calculated boundaries that define the expected range of variation for a process operating under common cause variation. Data points falling outside these limits signal the presence of special cause variation, indicating the process is out of control.
Question 12: Which of the following statements regarding control and specification limits is correct?
- It is best practice to set Control Limits narrower than Specification limits
- A suitable control chart and the right control limits will help to differential special cause variation from common cause variation. (Correct answer)
- Control limits are set by the customer
- Specification limits are set by the process owner
Correct answer: A suitable control chart and the right control limits will help to differential special cause variation from common cause variation.
Control charts are essential tools in Statistical Process Control (SPC) for differentiating between common cause variation (inherent to the process) and special cause variation (due to assignable factors). A suitable control chart with correctly calculated control limits provides the visual and statistical basis to make this distinction, enabling appropriate management action.
Question 13: What choice is made when the level of significance for a Moods Median test is set at 0.05 and the p-value is 0.02?
- Fail to reject null hypothesis
- Cannot determine
- Reject null hypothesis (Correct answer)
- Use a different test
Correct answer: Reject null hypothesis
In hypothesis testing, the decision rule states that if the p-value is less than or equal to the chosen level of significance (alpha), the null hypothesis is rejected. With a p-value of 0.02 and a significance level of 0.05, since 0.02 < 0.05, the null hypothesis is rejected, indicating a statistically significant result.
Question 14: SPC stands for?
- Statistical Process Control (Correct answer)
- Standard Planning for Control
- System Performance Charting
- Standard Process Charting
Correct answer: Statistical Process Control
SPC is an acronym for Statistical Process Control. It is a methodology that uses statistical methods to monitor, control, and improve a process. By analyzing process data, SPC helps identify and eliminate sources of variation, ensuring that a process operates consistently and produces high-quality outputs.
Question 15: Which of the following would be anticipated to be produced over the long term by a process with a process Sigma level of 6?
- Approximately 3.4 defects per 1 Million Success Opportunities
- Approximately 3.4 defects per 1 Million Process Opportunities
- Approximately 3.4 defects per 1 Million Defect Opportunities (Correct answer)
- Approximately 3.4 defects per 1 Million Products
Correct answer: Approximately 3.4 defects per 1 Million Defect Opportunities
A process operating at a Six Sigma level is designed to produce an extremely low rate of defects. Specifically, it is anticipated to produce approximately 3.4 defects per 1 Million Defect Opportunities (DPMO) over the long term. This metric accounts for a 1.5 sigma shift, representing a very high standard of quality and process capability.
Question 16: What level of training is a required for a member of a Lean Six Sigma process improvement team?
- Yellow Belt (Correct answer)
- Green Belt
- Black Belt
- Master Black Belt
Correct answer: Yellow Belt
In the Lean Six Sigma hierarchy, a Yellow Belt typically represents the foundational level of training. Yellow Belts are team members who possess a basic understanding of Lean Six Sigma principles and tools, enabling them to support Green Belts and Black Belts on projects and contribute to process improvement efforts within their own work areas.
Free Lean Six Sigma Green Belt Assessment Questions and Answers
There is a ____ if the correlation coefficient is between 0.5 and 1.