Free LSSGB Questions and Answers — Questions and Answers

Question 1: A rubber tire manufacturer is assessed based on five opportunities for each product; if 100 flaws are found out of 1000 goods produced in a month, the Rolled Throughput Yield is:

99%
96%
97%
98% (Correct answer)

Correct answer: 98%

Rolled Throughput Yield (RTY) is the probability that a process will produce a defect-free unit. To calculate the yield per opportunity: first, determine the Defects Per Opportunity (DPO). There are 100 flaws found in 1000 goods, with 5 opportunities per good, totaling 1000 * 5 = 5000 opportunities. DPO = 100 flaws / 5000 opportunities = 0.02. The yield per opportunity is then 1 - DPO = 1 - 0.02 = 0.98, or 98%.

Question 2: The Lean philosophy is what?

Reducing cost and improving purchasing power for the individuals
Provide perfect value to the customer through a perfect value creation process that has zero waste (Correct answer)
Continuous Improvement
Higher output by encouraging people to work hard and have targets

Correct answer: Provide perfect value to the customer through a perfect value creation process that has zero waste

The Lean philosophy is centered on providing perfect value to the customer through a perfect value creation process that has zero waste. It focuses on identifying and eliminating all forms of waste (Muda) in a process to maximize efficiency and deliver exactly what the customer needs, when they need it, with the highest possible quality. This continuous pursuit of perfection aims to create a seamless flow of value.

Question 3: What is claimed to be true when samples are randomly selected from a population?

The sampling distribution approaches normality with increase in sample size (Correct answer)
The sampling distribution would be triangular if population is distributed as triangular distribution
The sample mean is always the same as population mean
The sample standard deviation will be the same as population standard deviation

Correct answer: The sampling distribution approaches normality with increase in sample size

When samples are randomly selected from a population, the Central Limit Theorem (CLT) states that the sampling distribution of the sample mean will approach a normal distribution as the sample size increases, regardless of the original population's distribution shape. This fundamental theorem is crucial for inferential statistics, allowing for the use of normal distribution properties to make inferences about population parameters.

Question 4: Which of these qualifies as a technique for gathering consumer information or feedback?

Nominal Group Technique
Focus Groups (Correct answer)
Multivoting
Customer needs prioritization

Correct answer: Focus Groups

Focus Groups qualify as a technique for gathering consumer information or feedback. They involve bringing together a small group of customers or stakeholders to discuss their perceptions, opinions, beliefs, and attitudes towards a product, service, concept, or idea. This qualitative research method allows for in-depth exploration and understanding of the 'Voice of the Customer' through interactive discussion.

Question 5: The formula for Sum Square of Error is:

Sum Squares due to Pure Error - Sum Squares due to Lack of Fit
Sum Squares due to Lack of Fit-Sum Squares due to Pure Error
Sum Squares due to Pure Error + Sum Squares due to Lack of Fit (Correct answer)
None of the above

Correct answer: Sum Squares due to Pure Error + Sum Squares due to Lack of Fit

In regression analysis and ANOVA, the Sum of Squares of Error (SSE) represents the variation in the dependent variable that is not explained by the model. This error can be further decomposed into two components: the Sum of Squares due to Pure Error (SSPE), which accounts for the variation within replicate observations, and the Sum of Squares due to Lack of Fit (SSLOF), which measures how well the model fits the data beyond the pure error. Therefore, SSE = SSPE + SSLOF.

Question 6: What choice is chosen when the p value for the Moods Median test is.02 and the level of significance is set at.05?

fail to reject null hypothesis
cannot determine
use a different test
reject null hypothesis (Correct answer)

Correct answer: reject null hypothesis

In hypothesis testing, if the p-value is less than the chosen level of significance (alpha), we reject the null hypothesis. Here, the p-value of 0.02 is less than the significance level of 0.05. This indicates that the observed result is statistically significant, providing sufficient evidence to conclude that there is a difference in medians.

Question 7: What kind of waste could the ensuing circumstance generate? More clothes is being produced than what the customer has ordered by a clothing manufacturer.

Over Production (Correct answer)
Transportation
Over Processing
Waiting

Correct answer: Over Production

Producing more goods than what is immediately required or ordered by the customer is a classic example of 'Over Production' waste in Lean Six Sigma. This type of waste leads to excess inventory, consumes unnecessary resources, and can hide other inefficiencies within the manufacturing process. It often results in increased storage costs, potential obsolescence, and inefficient use of labor and materials.

Question 8: With effective SPC implementation in a process, Control Limit and Center Line calculations can be set up over a periodic time period.

False
True (Correct answer)

Correct answer: True

True. With effective Statistical Process Control (SPC) implementation, Control Limits and the Center Line are calculated based on historical data collected over a specific period. These calculations establish the natural variation and average performance of a stable process. Once set, they are used to monitor the process over subsequent time periods to ensure it remains in statistical control and to detect any unusual shifts or trends.

Question 9: The most current data point is normally on the right hand side of SPC charts, where the data are displayed.

False
True (Correct answer)

Correct answer: True

True. SPC charts are time-series plots designed to display process data in chronological order. Data points are plotted from left to right, with the horizontal axis representing time. Consequently, the most recent data point, reflecting the current state of the process, is always located on the rightmost side of the chart, allowing for real-time monitoring and trend analysis.

Question 10: Which statement or statements best describe a bad SPC implementation scenario?

A process is in Statistical Control before implementation of SPC
The Control Limits are wider than the customer specification limits (Correct answer)
Attempt to use SPC for tracking transaction times at a warehouse
The lower Control Limit for the R chart is equal to zero

Correct answer: The Control Limits are wider than the customer specification limits

A bad SPC implementation scenario occurs when the process's natural variation, represented by the Control Limits, is wider than the customer's acceptable range, defined by the Specification Limits. This means that even when the process is in statistical control, it is still producing outputs that do not meet customer requirements, leading to defects. An effective SPC implementation aims for Control Limits to be well within Specification Limits, indicating a capable process.

Question 11: Which set of charts is ideal if continuous data is subgrouped and a process has outliers?

nP and P Charts
Xbar-S Charts
Xbar-R Charts (Correct answer)
Individualג€"Moving Range

Correct answer: Xbar-R Charts

Xbar-R Charts are ideal for continuous data that is collected in subgroups, especially when the subgroup size is small (typically 2-10). The R-chart (Range chart) is particularly effective for monitoring process variability and is less sensitive to individual outliers within small subgroups compared to an S-chart. This combination allows for robust monitoring of both the process average (Xbar) and its spread (Range).

Question 12: Which graphic would be used to search for trends in the data after a Belt has smoothed the data?

Multi-Vari Chart
X bar Chart
Pareto Chart
Moving Average Chart (Correct answer)

Correct answer: Moving Average Chart

A Moving Average Chart is specifically used to smooth out short-term fluctuations and noise in data, making it easier to identify underlying trends or patterns. By plotting the average of a set number of consecutive data points, it reduces the impact of random variation. This technique is particularly useful after initial data smoothing to reveal the longer-term direction or shifts in a process that might otherwise be obscured.

Question 13: A Belt creates a Control Plan to bring a Lean Six Sigma project to a close. When may the Control Plan be shut down?

Within 30 days of the LSS project review team meeting
Never, a Control Plan is a living document (Correct answer)
After the project has been presented at the recognition event
As soon as the Champion signs off

Correct answer: Never, a Control Plan is a living document

A Control Plan is a living document in Lean Six Sigma, designed to ensure that process improvements are sustained over the long term. It is not meant to be shut down, but rather continuously reviewed and updated as process conditions, customer requirements, or best practices evolve. Its purpose is to maintain process stability and performance indefinitely, making it an ongoing part of process management.

Question 14: Sometimes a Belt will conduct a brief experiment known as an OFAT, which stands for ________.

Ordinary Fractional Approach Technique
One Factor At a Time (Correct answer)
Opposite Factors Affect Technique
Only a Few Are Tested

Correct answer: One Factor At a Time

OFAT stands for 'One Factor At a Time' experimentation. This method involves changing only one input variable while keeping all other variables constant to observe its individual effect on the output. While often less efficient than more complex Design of Experiments (DOE) methods for understanding interactions, OFAT is a simple and quick approach for initial screening of factors or troubleshooting specific process issues.

Question 15: Which of the following statements regarding the fitted line plot is true?

The predicted output Y is close to -18 when the Reactant level is set to 6. (Correct answer)
When Reactant increases, the Energy Consumed increases.
Over 85 % of the variation of the Energy Consumed is explained by the Reactant via this Linear Regression. (Correct answer)
The slope of the equation is a positive 130.5.

Correct answer: The predicted output Y is close to -18 when the Reactant level is set to 6.

In a fitted line plot, the regression equation allows for the prediction of the output (Y) for a given input (X). If the specific regression equation for this plot yields a Y value close to -18 when the Reactant level (X) is 6, then this statement is true. This demonstrates how the fitted line model can be used to estimate outcomes based on specific input variable settings.

Question 16: The actual experimental response data did not match up exactly with what a Belt had anticipated. Which of these has led to this?

Confounded data
Gap Analysis
Residuals (Correct answer)
Inefficiency of estimates

Correct answer: Residuals

Residuals represent the difference between the actual observed data points and the values predicted by a statistical model, such as a regression equation. When experimental response data does not perfectly match anticipated outcomes, these discrepancies are quantified as residuals. They indicate the unexplained variation or error in the model, providing insight into how well the model fits the data.

Free LSSGB Questions and Answers

A rubber tire manufacturer is assessed based on five opportunities for each product; if 100 flaws are found out of 1000 goods produced in a month, the Rolled Throughput Yield is: