IASSC LSSGB EXAM Questions With Complete Solutions!!

If the chance that any one of five telephone lines is busy at any instant is 0.01, then what is the probability that all the lines are busy? A. (0.01)^4 B. (0.01)^5 C. (0.01)^6 D. (0.01)^10 B. (0.01)^5 N = 5, p = 0.01, x = 5 Apply Standard formula for Binomial Distribution. Thus, option b is the correct answer. Who should complete the control phase after the successful completion and implementation of the first four phases of DMAIC? A. The green belt alone; the project has been successfully completed. B. The process owner alone; it is his responsibility to take the project from here. C. The process owner and the Green Belt together should complete the control phase. D. The complete team is the most desirable option. D. The complete team is the most desirable option. The control phase should be completed by the entire team. Control is not an insignificant phase of the DMAIC process. The green belt or the process owner alone may not have the ability and knowledge to structure the last control step. So option d is correct. To increase the power of the experiments, what is the best choice in the hands of a Six Sigma team? A. Increase Sample Size B. Reduce Sample Size C. Reduce Significance level D. All of the above A. Increase Sample Size Options b and c are not serious considerations, and thus option d can be ruled out. Conceptually, increase in sample size increases the possible accuracy of the experiment, and thus an increase in power. So, option a is the correct answer. Hypothesis testing is usually done to: A. Statistically validate if a sample mean belongs to the population B. Statistically validate if means of two groups are the same or if they are significantly different C. Statistically validate if variances of two groups are the same or if they are different. D. All of the above D. All of the above Statistically validate if a sample mean does belong to the population, find if means of two groups are the same or if they are significantly different, and validate if variances of two groups are the same or if they are different. Option d is the correct answer. What is the concept behind PDCA? A. The Deming/Shewhart cycle B. Process flow C. Continuous improvement D. Satisfying suppliers C. Continuous Improvement The key question phrase is "concept behind." Option b is inappropriate and does not fit the question. Option a would be correct if the question requested another name for PDCA. Answer option d could be one of the number of potential positive outcomes of this activity. However, the concept behind and objective of PDCA is that of continuous improvement. What are the six experiments called while performing one experiment with five repetitions? A. Randomization B. Replications C. Planned grouping D. Sequential B. Replications Repeated trials or replications are often conducted to estimate the pure trial-to-trial experimental error so that lack of fit may be evaluated. Randomization frees an experiment from the environment and other biases. Sequential experiments are conducted one after another, not all at the same time. Adjustments may be made in the experimentation based upon the knowledge obtained. Almost any DOE contains planned grouping. So answer option b is correct. Which type of chart is used for small shifts in variation? A. Xbar B. p C. c D. CUSUM D. CUSUM The other charts are traditional control charts that are designed to identify significant shifts in process variation, while the CUSUM chart is designed to show small variation shifts What are the distinct types of variation that are noted down in control charts? A.Special and assignable B. Random and chance C. Chance and assignable D. Normal and random C. Chance and assignable Chance and assignable are the two varieties of variation. Chance variation is also referred to as normal or random (among others). Assignable variation is also called special or non-normal. So option c is correct. Which of the following is an advantage of the production of a product in large lots? A. Machine efficiencies B. Customer delivery lead times C. Product transportation D. Product quality A. Machine efficiencies According to the proponents of lean manufacturing and continuous flow, options b, c, and d are all disadvantages. For large lot processing delivery lead times increases, transportation of products increases, and products have more potentiall for damage. Option a is generally recognized as the main advantage of large batch runs that may be more than offset by the disadvantages. So option a is the correct choice. A sample is to a statistic as a population value is to a: A. Sample B. Unit C. Parameter D. Measurement C. Parameter A statistic is derived from a sample. A parameter is derived from a population. So option c is correct. A calculation for reproducibility results in a value of 0 (zero), while repeatability yields a positive number. Without any other considerations, what conclusion can be made regarding the reproducibility result? A. The number of distinct categories is small compared to the appraiser variation. B. Operator influence in the measurement is the main cause of variation. C. Repeat the calculations; no conclusion can be determined without a reproducibility value. D. A reproducibility of zero means there is no operator effect on this measurement. D. A reproducibility of zero means there is no operator effect on this measurement. It is possible to have a reproducibility result of zero when studying automated equipment. Sometimes the appraiser only places a part in an instrument and an automatic reading is recorded in a database. There is no appraiser or operator effect in this kind of measurement, therefore, reproducibility is zero. So option d is correct. Historically, the number of flaws in the finish of surface has an average of 0.45. What is the probability of a randomly selected item having more than one defect in the surface finish? A. 0.0755 B. 0.2869 C. 0.6376 D. 0.3624 A. 0.0755 The Poisson distribution is used to model rates. The probability of exactly "r" events occurring can be computed using the Poisson distribution shown below. Entering values as r = 0 and myu value = 0.45 in the required equation gives the probability of exactly zero defects as 0.6376. Entering values as r = 1 and myu value = 0.45 in the same equation gives the probability of exactly 1 defect as 0.2869. The probability of less than 2 defects is 0.6376 + 0.2869 = 0.9245. Thus, the probability of more than 1 defect is 1 - 0.9245 = 0.0755. So answer choice a is correct. Why are scatter diagrams are useful in problem-solving? A. They display the significant few. B. They eliminate the trivial many. C. They show relationships between variables. D. They highlight assignable causes. C. They show relationships between variables. This question requests a positive response. Options a and b describe the Pareto diagram. Option d is one advantage of control charts (perhaps histograms as well). A scatter diagram depicts the relationship between variables. Specifically, an input variable may have an effect on an output variable. So answer option c is correct. The advantage of using the modern designed method of experimentation, rather than the classical OFAT, is that: A. Everything is held constant except the factor under investigation. B. Experimental error is recognized but need not be stated in quantitative terms. C. Fewer terms and measurements are needed for valid and useful information. D. The sequence of measurement is often assumed to have no effect. C. Fewer terms and measurements are needed for valid and useful information. The key to this question is the meaning of the word 'classical'. To most authors, this term refers to varying one factor at a time (OFAT) while holding all other factors constant. Although this approach may work for very simple problems, it causes havoc with moderately complex systems. The fixed factors do vary, which can waste time, effort, and money. This traditional approach can yield invalid or inconclusive results. Modern design experimentation (including fractional factorials, improved three factor designs, and Latin square logic) squeeze a large amount of valid information from a few trials. Option c is correct. What does ANOVA stands for? A. Analysis of Variance B. Analysis of Variables C. Accuracy of Variance D. Analysis and Validation A. Analysis of Variance Which of these quality tools would NOT be expected to be used during the results confirmation stage of a problem solution ? A. Flow chart B. Pareto diagram C. Histogram D. Control chart A. Flow Chart Note that a negative response is requested. The results confirmation stage uses performance data collection and analysis tools such as check sheets, Pareto diagrams, histograms, and control charts. The flow chart is normally used earlier in the problem-solving process, often to help define the problem. Answer a is the suitable choice. If 6 consecutive samples were taken from a process and precisely measured, you can still expect differences. What type of variation would be the most difficult one to determine? A. Lot-to-lot variation B. Piece-to-piece variation C. Inherent process variation D. Error of measurement A. Lot-to-lot variation The small sample size would make it impossible to give a high level of confidence in the results. However, inherent process variation, piece-to-piece variation, and measurement error are obtainable. Lot-to-lot variation would not be detectable unless carefully planned for (which is not indicated in the question). So option a is correct. Which of the following inference tests does NOT require the knowledge of a test or population variation? A. t test B. Paired t test C. z test D. Chi-square test D. Chi-square test Note that a negative response is requested. All of the above require population or sample variance (or standard deviation) except the chi-square test (with sup6 2 unknown). Option d is correct. Which of the following is the LEAST likely candidate to assist in the problem definition stage of Six Sigma? A. CTQ trees B. Pareto analysis C. Product yield data D. Control charts D. Control charts Note that a negative response is requested. Items like CTQ trees, Pareto, yield data, customer feedback, and so on are useful for project definition. Control charts occur much later in the DMAIC cycle. So answer d is the correct choice. What is the name of the condition if you are running a 7-4 fractional experiment? You know factors A, B, C, D, and E are independent of each other, but you suspect factors F and G are not independent. You conducted a small sub-experiment and discovered a high correlation between factors F and G. A. Collinearity B. Confounded C. Correlation D. Covariates A. Collinearity Having two variables that are highly correlated in the experimental model will make it difficult or impossible to detect which factor really affects the response. This condition is called collinearity. The correct answer is option a. Which of the techniques used in DOE helps you in eliminating errors due to nuisance factors? A. Replication B. Blocking C. Randomization D. Coding B. Blocking By creating blocks in an experiment, you can eliminate the errors due to nuisance factors and thus option b is the correct answer. If P(A) is 0.6 and P(B) is 0.5 and the probability of either event happening is 0.85, what is the probability of both the events occurring? A. 0.25 B. 0.3 C. 0.35 D. 0.4 A. 0.25 0.85 = P(A) + P(B) - P(A&B) = 0.6 + 0.5-0.85 = 0.25. Thus, option a is the correct answer. A process has high variability and an off-centered mean. What is the first action the team needs to take? A. Center the mean B. Reduce Variations C. Increase the specifications D. None of the above A. Center the mean For this process, centering the mean will bring a lot of the non-conforming possibilities within the specification limits. Option a is the answer. What is the use of Scatter Diagrams A.Control the process B. Display the order of tasks or events C. Display correlation D. Identify root causes C. Display correlation Control charts usually do the process controlling. A display of tasks or events may be accomplished with a flow chart or checklist. Cause-and-effect diagrams can help identify root causes. Scatter diagrams are used to display correlation. So option c is correct. Five samples are drawn out of a population of 200, with each sample being of size 5. The sample means are 2, 2.5, 3, 2.6, and 4. What is the sample mean? A. 2.8 B. 3 C. 3.2 D. 3.4 A. 2.8 According to CLT, the sample mean is the mean of all the sample means. Taking an average of all the sample means, the answer is 2.82 which is close to 2.8. Option a is correct. In IT sector, time and effort spent in testing the software, fixing bugs, and retesting would be considered as what type of waste? A. Waiting B. Over Production C. Defects D. Over Processing C. Defects Any effort spent on testing, bug fixes, and retesting would be considered as waste of type defects. If this was done right the first time, we would not have this waste. What is the need to plot data points on the least squares line if a probabilistic regression model exists? A. To visually present the relationship to others B. To check for fit; there may be a calculation error C. No rational reason for doing so D. To permit a projection outside of the test area B. To check for fit; there may be a calculation error The best answer is b. There may be a mathematical error. The second best answer is a. Answer option c is incorrect and option d is always risky. A team of Six Sigma has reached the control stage of DMAIC. The team has successfully reduced the defect of fabric critical stains from 73 to 1 per fabric roll. Now what type of control chart should the team recommend? A. A control chart based on the normal distribution such as the X-bar chart B. A control chart based on the Poisson distribution such as the u-chart C. A p-chart based on the binomial distribution D. An np chart based on the binomial distribution B. A control chart based on the Poisson distribution such as the u-chart All four answers refer to valid control charts, but only answer B recognizes the Poisson nature of the improvement achieved. Critical stains are defect counts which are descriptive of the Poisson distribution. All other chart options are improper applications. Option b is correct What would be considered the most important element in the deployment of Six Sigma? A. Training B. Organizational structure C. Management support D. Reward and recognition C. Management support All of the answer choices are key Six Sigma elements. However, the question states the "most important element." Management support is the most important element listed. What is the attempt to reduce the impact of human error in a process called? A. Poka-yoke B. Jidohka C. Kaizen D. Muda A. Poka-yoke What is the major weakness of the one-factor-at-a-time experimental strategy? A. It offers no ability to vary factors together. B. It fails to account for interactions between factors. C. It can be more costly to conduct. D. It is less efficient than designed experiments. B. It fails to account for interactions between factors. All the items present good arguments against the one-factor-at-a-time testing. However, the major disadvantage is the failure to account for interactions. So answer b is correct. Process capability (Cp) describes a process, often in a stable manufacturing environment, which leads to the production of a product that conforms to client and design specifications. What will be the Cp value of an ideal process? A. Greater than 1 (1) B. Less than 1 (1) C. Equal to 1 D. Within 1 standard deviation of mean A. Greater than 1 (1) An ideal process will have a Cp value 1 in a stable environment. Option a is the correct answer. What does OEE stands for? A. Overall Equipment Effectiveness B. Overall Estimation Effectiveness C. Overall Equipment Estimation D. Overall Effective Estimation A. Overall Equipment Effectiveness The determination of temporal variation in multi-vari charting means: A. Variation within piece B. Variation over time C. Variation piece-to-piece D. Variation within batch B. Variation over time Temporal variation means variation over time Which of the following pairs is the most useful in preparing control charts, when used together, for variables data? A. AQL, p-bar B. p, n C. X-bar and R D. R, sigma C. X-bar and R An X-bar and R chart are represented best by variables data. Options a and b list attribute data quantities. The two values in option d are measures of dispersion and are not used together in control charting. So option c is correct. Which of the following describes internal failure costs? A. The economic costs associated with a catastrophic failure of an internal subsystem B. The unavoidable quality system costs associated with the production of any product or service C. The opposite of external failure costs D. The costs resulting from a nonconformance detected before a product or service is provided D. The costs resulting from a nonconformance detected before a product or service is provided The nonconformance costs are related to processes that do not match the customer expectations and hence relate to internal failure costs. If an experiment has an alias, you could say that the two factor effects are: A. Confounded B. Blocked C. Misnamed D. Mixtures A. Confounded A design alias implies that the two factor effects are confused or confounded with each other. So option a is correct. Why would a Six Sigma practitioner use an EWMA chart? A. To identify special cause variation B. To identify common cause variation C. To identify small shifts in variation D. To take advantage of the fact that it's easier to use C. To identify small shifts in variation An Exponential Weighted Moving Average, or EWMA, chart is primarily used to indicate small shifts in process variation. What is the definition of Inventory type of waste? A. Storing parts at other location B. Any supply in excess to process requirements necessary to produce goods or services just-in-time C. Wrong parts in inventory D. Finding and removing defective inventory from the stock B. Any supply in excess to process requirements necessary to produce goods or services just-in-time Inventory type of waste refers to any supply in excess to process requirements necessary to produce goods or services just-in-time. So the correct answer is option b. Choose the control chart that is used to monitor discrete data in Lean Six Sigma Green Belt? A. p Chart B. I -MR Chart C. X Chart D. R Chart A. p Chart p Chart is the control chart that is used to monitor discrete data in Lean Six Sigma Green Belt. Which type of control chart is ideal for destructive testing? A. X bar chart B. p chart C. I chart D. u chart C. I chart The control chart that works best for destructive testing is an I chart since only one unit is required to plot results at a sing point in time. Which of the following is NOT a direct benefit of a Six Sigma project? A. Helps improve Cost of Quality B. Helps improve Customer Satisfaction C. Helps improve Supplier Quality D. Helps improve market share C. Helps improve Supplier Quality Six Sigma project helps in improving COQ, customer satisfaction, and also market share by increase in number of customers. Improving supplier quality is not a direct benefit of a Six Sigma project thus option c is the correct incorrect answer. When put together, what do Repetition and Replication help the Six Sigma team determine? A. Short-term variability B. Long-term variability C. Both A and B D. Neither A nor B C. Both A and B Repetition helps in determining short-term variability and Replication helps with long-term variability. Put together, they help in determining both. Thus, option c is the correct answer. Which of the following statements is NOT true with regard to regression analysis? A. The coefficient of determination ranges from 0 to 1. B. The correlation coefficient ranges from -1 to 1. C. The higher the coefficient of determination, the better the fit. D. Least squares is required to determine the best fit straight line. D. Least squares is required to determine the best fit straight line. Regression is a method of fitting a model to data. Least squares is the most common procedure, but other procedures are also available. The correlation coefficient, r, is a measure of the strength of the correlation. When r = 1, there is perfect positive correlation, and when r = -1, there is perfect negative correlation. The coefficient of determination, r squared, represents the portion of the variability in the data explained by the regression model. Answer option d is the correct choice. What set of basic quality tools would be most applicable for a work team to use when there is a desire to follow procedures and work instructions more closely? A. Pareto and affinity diagrams B. Data sheets and histograms C. Checklists and flow charts D. Fishbone and control charts C. Checklists and flow charts Histograms, fishbone charts, control charts, Pareto diagrams, and affinity diagrams have no application as memory aids. Data sheets, checklists, and flow charts might offer an advantage. Only answer choice c offers two of these tools. So option c is correct. Variable control chart subgroup sizes are generally 3, 4, 5, or 6 for all of the following reasons EXCEPT: A. They are large enough so that averages of data will follow the normal distribution B. They fit onto traditional chart paper very well C. Larger sizes permit an opportunity for process changes within the subgroup D. They permit a separation of within time from time-to-time variation B. They fit onto traditional chart paper very well Note that a negative response is requested. The weakest selection is option b. Control chart paper was developed to support a logical control chart sample size. Sample sizes should not be chosen to fit a handy form. The other items have merit. So option b is the correct choice. What is the variance for a distribution of means with a sample size of 36 and a population standard deviation of 3? A. 0.75 B. 0.5 C. 0.25 D. 1 C. 0.25 Applying CLT principles, Sample Standard deviation = 3/sqrt(36) = 0.5 and sample variance is thus the square of standard deviation. Option c is the correct answer. Which of the following is NOT an advantage of control charts? A. They can detect trends of statistical significance. B. They provide straightforward, easily interpreted information. C. They provide an ongoing measure of process capability. D. They can detect special causes of variation. B. They provide straightforward, easily interpreted information. Note that a negative response is requested. The advantages of control charts include their ability to detect trends of statistical significance, provide an ongoing measure of process capability, and detect special causes of variation. The disadvantage is that they can be difficult to interpret properly. So answer b is the correct. What is the most important benefit of implementing Lean? A. Achieving elimination of waste B. Achieving Continuous Flow C. Achieving financial gains D. Achieving reduction of NVA B. Achieving Continuous Flow Lean eliminates waste, helps in reduction of NVA, and also helps the company in achieving financial gains. But principally, the important benefit of implementing Lean is to achieve continuous flow of the product. Thus, option b is the correct answer. A Six Sigma team has been created to improve the process in which a company takes orders for its products. Which of the following tools should the team use to determine all the potential pitfalls and the actual defects that occur? A. Process failure mode and effects analysis B. Supplier input process output control C. Process map D. Design for Six Sigma A. Process failure mode and effects analysis A Process Failure Mode Effects Analysis (PFMEA) is a structured analytical tool used by an organization, business unit, or cross-functional team to identify and evaluate the potential failures of a process. PFMEA helps to establish the impact of the failure, and identify and prioritize the action items with the goal of alleviating risk. It is a living document that should be initiated prior to the process of production and maintained through the life cycle of the product. According to a national grocery store chain manager, only 6% of customers who have surveys mailed to their homes return them filled out completely. What is this type of sampling error called? A. Non-response error B. Confidence interval C. Lazy consumer error D. Mailing error A. Non-response error Which approach talks about equipment effectiveness? A. Lean B. TPM C. Six Sigma D. TOC B. TPM Total Productive Maintenance, or TPM, is focused on Overall Equipment Effectiveness (OEE), which completely focuses on equipment reliability and maintenance. So option b is the correct answer. Which Six Sigma role is most likely to define objectives for an improvement team? A. Leader B. Sponsor C. Facilitator D. Member B. Sponsor The team sponsor is often likely to define team objectives. The second best choice is the team leader, although this is usually not the case. Team facilitators and members do not define team objectives. Answer option b is correct. What is accuracy? A. Getting consistent results repeatedly B. Reading to one decimal greater than the reported dimension C. Using the best measuring device available D. Getting an unbiased true value D. Getting an unbiased true value A review of measurement terminology is required. Getting consistent results repeatedly is precision. Reading to one decimal greater than the reported dimension has to do with the sensitivity of the device. Using the best measuring device available can be costly and unnecessary. The correct choice is getting an unbiased true value. What should the Six Sigma Green Belt do in terms of actions if Cp = 1.3 and Cpk = 0.8? A. Center the mean B. Reduce variations C. Reduce variations and center the mean D. Nothing A. Center the mean The variations seem to be under control as indicated by the Cp value. The change in Cp and Cpk could be because of shift in the mean, which needs to be centered. Option a is the correct answer. Which of the following is used to test the equality of medians from two or more different populations? A. Mood's Median B. Kruskal-Wallis C. Friedman D. 1 Sample Sign Test A. Mood's Median The Mood's Median is a nonparametric test used to test the equality of medians from two or more different populations. While plotting a multi-vari chart on the graph paper, what metric is used for the horizontal scale? A. Time B. Count data C. Variable data D. Percentages A. Time In multi-vari charting, time (or sample number in time sequence) is shown on the horizontal scale and a variable measurement (usually with locational identification) is shown on the vertical scale. So option a is correct. What is the basic assumption of null hypothesis? A. That the variables are dependent B. That the variables are independent C. That the sample size is adequate D. That the confidence interval is A± 2 standard deviations B. That the variables are independent Option d is a filler option. It is desirable that the sample size be adequate (option c), but sufficient information may not be available to determine an adequate sample size before testing. One assumption made in the analysis of variance of means is that the variables are independent. So answer b is correct. Which of the following does an F distribution closely resemble? A. A t-distribution B. A Chi-square distribution C. An exponential distribution D. A log normal distribution B. A Chi-square distribution The F statistic is the ratio of two sample variances (two chi-square distributions). It should come as no surprise that it resembles a chi-square distribution in appearance. So answer option b is correct. In hypothesis testing, if someone stated one minus the level of confidence risk, then which of the following statistics would be under consideration? A. The alpha risk B. The 1-alpha risk C. The beta risk D. The 1-beta risk A. The alpha risk The first observation made would be that the experimenter is probably confused. If the statement is correct, then: 1-alpha risk = level of confidence or 1-level of confidence = alpha risk. So option a is correct. Which of the following best defines "Overproduction" type of waste? A. Producing in excess of need or specified amount B. Producing over and above the capacity of the machine C. Parts produced over the specified measurements D. Parts produced during over time shift A. Producing in excess of need or specified amount A ''pull'' production system is a production system where you make as much product as you can regardless of whether the customer needs it or not. A. True B. False B. False A Pull production system only make the amount needed to meet the customer's specific demands. An engineer is considering a fractional factorial instead of a full factorial to analyze a process because of the large number of variables under study. Apart from the possibility of studying a large number of factors with relatively few experiments, what other characteristic will support a decision to use a fractional factorial instead? A. It is suspected that there are many interactions. B. The process is well known and only the main factors are of concern. C. A fractional factorial will determine the main effects curvature. D. Blocking is necessary to account for nuisance factors in this study. B. The process is well known and only the main factors are of concern. Answer options a and c are conceptually wrong. Options b and d are valid concepts but only option b responds to the question. A good reason to use a fractional factorial is that one knows the process and has no immediate concerns about factor interactions. Answer option b is correct. In the theory of control charts, the distribution of the number of defects per unit very closely follows the: A. Normal distribution B. Binomial distribution C. Chi-square distribution D. Poisson distribution Poisson distribution The normal distribution relates to variable data and not attribute data. The chi-square distribution is used to make inferences regarding population variances. The binomial distribution is assumed for defectives. The Poisson distribution is assumed for defects. So option d is correct. What are the typical phases of Six Sigma-based Improvement methodology? A. DMAIC (Define, Measure, Analyze, Improve, Control) B. PDCA (Plan, Do, Check, Act) C. Reduce Variation D. Sort, Stabilize, Shine, Standardize, Sustain, Support A. DMAIC (Define, Measure, Analyze, Improve, Control) Conceptually, which tool used in the Six Sigma DMAIC implementation resembles the Process Decision Program Chart? A. FMEA B. Pareto Charts C. VOC Analysis D. QFD A. FMEA Of all these tools, FMEA can be used to plan contingency, which is the primary purpose of PDPC. Option a is the correct answer.