Green Belt Exam Questions
When analyzing a process, which of the following terms represents the inputs? a. f(X) b. X c. Y d. Result e. Cost
Answer B f(X) is the Transfer Function; Y is the process output, also sometimes referred to as the Result; Cost could be either an input or output. Please reference Input Determines Output for more information.
A process improvement team brainstorms a list of 42 improvement ideas for a particular problem. The team proceeds to multivoting to narrow down the ideas. How many votes should each team member get? a. 30 b. 5 c. 10 d. 25 e. 20
Answer E Each team member should get between one-third and one-half of the ideas (14 - 21). Please reference Narrowing Down The List of Ideas for more information.
"Poka Yoke" is a Japanese term for what activity? a. 100% inspection b. Continuous Improvement c. Benchmarking d. Just-in-time inventory e. Error-proofing
Answer E This is true by definition. Please reference Error-proofing for more information.
At which stage of a Six Sigma DMAIC project is a process map typically created? a. Define b. Measure c. Analyze d. Improve e. Control
Answer A A process map helps to define the project and organize subsequent improvement efforts. Please reference The Source of Value for more information.
In which of the following scenarios would a Pareto chart most likely be employed? a. To show the relative frequency of defects in rank order. b. To assess the strength of the relationship between potential causes and effects. c. To show trends in data over time. d. To investigate the effect of discrete inputs on continuous outputs. e. To show the relative frequency of observations within categories.
Answer A Answer A = Pareto chart, Answer B = Cause-Effect Matrix, Answer C = Trend chart, Answer D = Box Plot, Answer E = Histogram. Please reference Pareto Chart Toolset for more information.
In which stage of the Six Sigma DMAIC process is a charter established? a. Define b. Measure c. Analyze d. Improve e. Control
Answer A Creation of the charter is the first project step. Please reference Project Charter Toolset for more information.
Why is it useful to identify CTQC's rather than general requirements statements? a. They are more specific and are easier to measure and control. b. They allow price reduction for suppliers. c. They enable calculation of the cost of quality. d. They can be eliminated once they are identified. e. The are always stable and capable.
Answer A Critical To Quality Characteristics are the "What's", which can then prompt identification of "How's". They should be specific enough to be measurable. Please reference CTQC Tree Diagram Toolset for more information.
An improvement team has finished recording customer requirements. Which of the listed quality tools can be used to organize the data? a. Affinity diagram. b. Pareto chart. c. Run chart. d. FMEA. e. Histogram.
Answer A The affinity diagram is one of the best tools for organizing data. The purpose of the other tools is more for analysis than for organization or grouping. Please reference Affinity Diagram Toolset for more information.
Two sets of data of n=25 are compared using the t-test to test the null hypothesis that these data sets came from the same population at a 0.05 alpha level. Sample A has a mean of 25, and Standard Deviation of 0.6, while Sample B has a mean of 27 and a Standard Deviation of 0.3. Assume that the variances of the two populations are equal. Which is the correct conclusion? a. We reject the null hypothesis b. We accept the null hypothesis c. We cannot reject the hypothesis d. The means are equal e. The sample size is too small to draw any conclusions
Answer A The two-tailed cut-off value then is t with (25+25-2 =) 48 d.f. = +/- 2.01. A t-statistic value of -14.91 exceeds the cut-off value of +/- 2.01, which means that the probability that they come from the same population is extremely low. Therefore, we reject the hypothesis. Please reference Comparing Two Means - t-test Toolset for more information.
What will a stakeholder analysis (RACI matrix) help the team do? a. Narrow the project scope. b. Reduce the likelihood of project roadblocks. c. Choose effective team members. d. Develop a focused problem statement. e. Choose the most optimal project to pursue.
Answer B A stakeholder analysis is used to 1) identify those entities that will have influence on the project, 2) identify the type of influence and 3) develop strategies to realize the positive influences and reduce any roadblocks due to the negative influences. Please reference Stakeholder Analysis - RACI Matrix for more information.
Which of the following tools is used to prioritize categories based on relative frequency of occurrence in the search for a root cause or key variable? a. Affinity Chart b. Pareto Chart c. Cost Analysis d. Process Flow Chart e. Histogram
Answer B Affinity Charts are use for grouping; Cost Analysis might help find a root cause, but only to a cost problem; Process Flow Charts don't provide prioritization; Histograms are used to provide a picture of process spread (variation). Please reference Pareto Chart Toolset for more information.
Which is NOT a description of an organized and effective team? a. Team members each work with specific performance measures. b. Team members are informal about who works on what. c. Team members are selected with their complementary skills in mind. d. Team members each share accountability for the results and outcome of the project. e. Each team member has a specific objective for their project.
Answer B An effective team allocates responsibilities among the team members in a mindful, organized manner. Please reference Leading Teams for more information.
What is the over-arching (primary) objective of Lean Methods? a. Achieve zero defects b. Eliminate all waste c. Continuously improve d. Minimize cycle time e. Achieve continuous flow
Answer B Answers A, C, D and E are Lean techniques used to work toward the larger objective of eliminating all waste. Please reference Continuous Flow Toolset for more information.
What is the Mean, Mode & Median for the data in Column 1, Data Set A? a. Mean = 8.7, Mode = 8, Median = 7 b. Mean = 8.7, Mode = 7, Median = 8 c. Mean = 8, Mode = 8.7, Median = 7 d. Mean = 7, Mode = 7, Median = 8.7 e. Mean = 8, Mode = 8, Median = 7
Answer B Formula: Mean = Sum(x)/n = 8.7 Mode = Most frequent value = 7 Median = because sample is even (n=50), the median is the average of the (n/2)th and ((n/2)+1)th values in the sorted series = 8 Please reference Quantifying Process Variability for more information.
In a FMEA, Error Proofing is used to reduce the RPN by targeting which of the following? a. Poor design b. Occurrence c. Detection d. Equipment e. Severity
Answer B If the failure never occurs, Detection and Severity are not as important. Please reference FMEA Toolset for more information.
In a failure mode and effects analysis (FMEA), we determine that probability of undercooking a meal has been reduced by improvement actions. Which best describes the revised RPN component? a. The Detection score increases b. The Occurence score decreases c. The Detection score decreases d. The Severity score decreases e. The Occurence score increases
Answer B If undercooking happens less frequently, the Occurence score would decrease. Detection happens after cooking, and is unaffected. Severity is also unaffected. Please reference FMEA Toolset for more information.
A series of processes is producing the defective level below. What is the Rolled Throughput Yield (assume only one defect per unit)? Process Step 1: 37 Defective, 1000 Units Process Step 2: 18 Defective, 1000 Units Process Step 3: 35 Defective, 1000 Units Process Step 4: 118 Defective, 1000 Units 1. 0.982 2. 0.805 3. 0.882 4. 0.195 5. 0.782
Answer B Multiply together the fraction of non-defective units from all the process steps: 0.963 * 0.982 * 0.965 * 0.882 = 0.805 Please reference Derivative Performance Metrics - Rolled Throughput Yield for more information.
An operational definition provides a clear acceptance standard. Which of the following are necessary parts of it? a. Voice of customer, Test, Shipment b. Standard, Test, Decision c. Experiment, R&R study, Inspection d. Inspection, Correction, Shipment e. Input, Process, Output
Answer B Operation Definitions include an objective standard, a method to test against that standard, and decision criteria to evaluate the test results. Please reference Operational Definition Toolset for more information.
Which of the following is a use for a Pareto Chart? a. Determining Process capability b. Learning the vital few (most common) types of defects c. Determining significance of operator errors d. Estimating measurement error e. Determining specific trends over time
Answer B Pareto Charts sort occurence by order of frequency. Please reference Pareto Chart Toolset for more information.
Which of the following process measures is discrete? a. Cycle time for a billing process b. Accuracy of a single item on a credit invoice. c. Time on hold for customers calling to all centers. d. Cost for rework for a loan application.
Answer B Please reference Discrete vs. Continuous Measurements for more information.
Data collection may be undertaken in all steps of the DMAIC cycle. In which step is data typically collected in order to establish a current baseline for an existing process? a. Define b. Measure. c. Analyze. d. Improve. e. Control.
Answer B The Measure phase of the Six Sigma DMAIC cycle is used to determine how we will know when we get to the goal, i.e., determine the baseline performance of the process so that comparisons can be made later on to validate any improvements made. Please reference Measurements and Basic Statistics for more information.
A call center was experiencing customer complaints about time-on-hold and an improvement team was formed to solve the problem. The manager of the call center joined the team's first meeting and informed the team that their project would be short-lived because the obvious solution to the time-on-hold problem was to add more phone lines. With this advice as a basis, the team crafted a problem statement: "Additional phone lines are needed in order to reduce the average customer time-on-hold from 6.2 minutes to our target of 45 seconds". Which of the following best describes the problem statement? a. The statement is too broad to be useful in the particular situation. b. The statement contains a solution. c. The statement is not related to the problem described above. d. This is a good problem statement. e. The statement does not fully define "time-on-hold".
Answer B The problem statement dictates that the solution is "additional phone lines". Please reference Project Charter for more information.
In SIPOC Map, what does the "I" represent? a. Investment b. Input c. Inspection d. Improvement e. Involvement
Answer B This is true by definition. Please reference Process Mapping (SIPOC) Toolset for more information.
In the statement Y=f(x), what does Y represent? a. The transfer function b. The process output of interest c. Process Capability d. An input variable e. An independent variable
Answer B This is true by definition. The process output (Y) is a function (f) of process inputs (Xs) Please reference Input Determines Output for more information.
135.657 - Customer Complaints Case This question refers to the "Customer Satisfaction" case. Download the "Complaints" file above, which shows the customer complaint history for 10 months, including the number of orders, number of complaints, and the cost of complaints. It also has a break-out of these complaints by cause (Note: assume one complaint per order). Your team is chartered to reduce the cost of complaints. To look at the 10 month period to see if the number of complaints as a % of orders is in statistical control, which attribute control chart should you use? a. np chart b. p-chart c. c chart d. u-chart e. Xbar-R chart
Answer B Varying sample size for % defective is p chart. Please reference Attribute Control Chart Toolset for more information.
Which of the following options are the least effective control method? a. Written Standard Operating Procedure (Standardized Work) b. Verbal Operator Training c. Control Charts (SPC) d. Error-Proofing Measures e. Visual Control Boards
Answer B Verbal instructions show only very temporary effects. Memory is never as good as controls which are designed-in, visible and durable. Please reference Visual Control for more information.
An improvement team is working with a delivery process to reduce the number of late deliveries. Which tool would be the best choice if the team intends to examine the variation exhibited by the current process over a period of time? a. Run Chart b. Pareto Chart c. Control Chart d. SIPOC Map e. Histogram
Answer C A control chart is the best tool to use in this situation because it can distinguish between common cause and special cause variation and provide insight into the best way to reduce variation in the process. None of the other tools listed do this. The run chart plots variation, but lack of control limits means less information is provided for analysis. The histogram also displays variation, but does not show changes in variation over time. Please reference SPC - Introduction to Control Charts for more information.
Which tool is used to convert brainstormed ideas into groups to better evaluate them? a. Spaghetti diagram b. Pareto chart c. Affinity diagram d. Quality Function Deployment e. Scatter diagram
Answer C Affinity Diagrams are used to sort raw information and establish recognizable groups or patterns. Please reference Affinity Diagram Toolset for more information.
A call center is tracking the number of seconds a caller must wait before speaking with a representative. If the measurement collected is "customers hold time", which of the following might give rise to common cause variation in the data collected. a. An occasional 'system crash', that reduce the number of operators by 50% for up to 20 minutes. b. The volume of calls received between noon and 1:00PM is three times greater than the call volume for the rest of the day. c. A wide range of experience and training among the operators. d. A flu virus in January reduces staffing at the call center by 75% for one week. e. A new product introduction with initial quality problems leads to a spike in customer calls.
Answer C Answers A, B, D, and E are all things that can happen intermittently, which lends itself to special cause variation. Answer C is the only one the is inherent to the process - therefore common cause variation. Please reference SPC - Control Chart Limits for more information.
Correlation Coefficient values have which of the following characteristics? a. Are always positive b. Indicate how much error there is in the measurement system c. Are always between +1 and -1 d. Both (b) and (c) e. Both (a) and (b)
Answer C By definition. Please reference Correlation and Regression Analysis for more information.
A fast food restaurant receives a large volume of drive-through orders. A Lean Six Sigma team wants to understand the resources required to maintain a maximum target cycle time of 4 minutes. When demand fluctuates, personnel can be reassigned temporarily to increase the rate of processing. If the normal processing rate is 40 seconds per order, what should the maximum customers in process (queue) be before reassigning resources? a. 2 b. 4 c. 6 d. 8 e. 19
Answer C Little's Law: Things-in-Process (Queue) = Cycle time x Demand = 4 minutes x (1 order/40 seconds) x (60 seconds/minute) = 6. Please reference Continuous Flow Toolset for more information.
The fishbone diagram is used for which of the following? a. To follow the movement of people in a process b. To determine process capability c. To categorize input variables that may be important d. To prioritize the highest frequency problems e. To show the process flow
Answer C Please reference Cause & Effect Diagram Toolset for more information.
Internal metrics indicate that a DMAIC project team has successfully reduced the number of shipping errors, which had been a significant source of customer dissatisfaction. The project manager held a meeting with the operations manager and controller to close the project by verifying that the requirements of the project were met and terminating the project budget. What element of closing a project is missing? a. Congratulating the team on a job well done. b. Reassigning unused resources to other projects. c. Confirming the results with the company's customer. d. Writing the final project report for management review. e. Nothing, all project close-out steps were followed.
Answer C Project close-out is the process of confirming with the customer of the project that their requirements have been met and that no additional development effort is required. After closing the project, the team should celebrate its success, and resources should then be reassigned. Please reference Ending the Project for more information.
Which of the following is NOT a requirement for moving to a pull scheduling type of system? a. Capable processes b. Small lot sizes c. Automated management systems d. Reliable equipment e. Stable demand
Answer C Pull scheduling can be successfully implemented as a 100% "manual" system. Automated systems can help but are not a requirement. The fifth requirement is a Close Supplier Network. Please reference Pull Scheduling for more information.
At a sigma level of 3 what is the expected number of defects per million opportunities? a. 3.2 b. 2700 c. 66,800 d. 30,000 e. 17,367
Answer C See Sigma Level calculator Please reference Calculating the Sigma Level - Toolset for more information.
A control plan should be designed to cover which of the following areas? a. Plant financial performance and internal controls b. A single characteristic and piece of equipment c. All significant process input and output characteristics d. Separate shifts on a process e. Daily inspection and reject results
Answer C The Control Plan is the centralized document used to keep track of the status of all significant characteristics. "Significant" means more than just "important", it implies a statistically significant relationship between an input (X) and an output (Y). Please reference The Process Control Plan for more information.
What is missing from the following Project Charter Business Case statement: "Process Cycle Time must be reduced in order to meet customer requirements" ? a. Team leader b. Scope of project, including "included" and "not included" c. Amount of improvement required and business impact d. Measurement system to be used e. Resources required
Answer C The business case should state the level of improvement required, otherwise, there will be no may to measure success. In addition, the economic impact should be included so that it is clear why this project is a priority vs. something else. Please reference Project Charter Toolset for more information.
This question refers to the "Customer Satisfaction" case. Download the "Complaints" file above, which shows the customer complaint history for 10 months, including the number of orders, number of complaints, and the cost of complaints. It also has a break-out of these complaints by cause (Note: assume one complaint per order). Your team is chartered to reduce the cost of complaints. Construct a control chart of the complaint rate over time. What does the chart tell you about the complaint rate? (assuming that 10 points is enough data) a. It is increasing b. It is decreasing c. It is in statistical control d. Month 4 is too high and we should seek a special cause e. There are many out of control points in the chart.
Answer C The chart is in control. Note: the limits on a p-chart are variable. Please reference Attribute Control Chart Toolset for more information.
A process improvement team piloted an improvement to a process that was not in control. The process specification is 8.5 units +/- 0.5 units. The results of the pilot run are shown below in an X and Moving Range chart. What conclusion can you draw from the pilot run? a. The new process is in control at an improved operating level, but the operating level has not improved - the change should not be implemented. b. The new process is not in control and the change should not be implemented because capability is still suspect. c. The new process is in control with an improved operating level and may be implemented, but additional actions are required to improve capability. d. The new process is not in control but the change can be implemented anyway to take advantage of the improvement while further actions are contemplated. e. More information is needed to be able to make any conclusions.
Answer C The process is in control and shows improvement on two levels after the pilot: the process mean is closer to target with a smaller variance. But the process is still not capable - before the improvement, ten out of twenty five data points were outside the specification limits; after the improvement only one is out of specification, showing a large reduction in out-of-spec parts. The team should implement the change and may continue to improve the process capability if the cost is justified. Please reference Piloting a Solution for more information.
This question refers to the "Claims Processing" case. A hospital processes claims and the insurance companies often reject them for coding errors. A Six Sigma team has been working on a project to reduce coding errors for the past 15 months and the data for the number and type of coding errors can be downloaded above in the "ClaimCoding" file. Use this data to answer the question below. Considering the attribute nature of code counts, what chart would you use to check whether the errors/claim are in statistical control over the time period? a. p-chart b. np-chart c. u-chart d. c-chart e. Pareto Chart
Answer C The u-chart should be used for defects per unit when the sample sizes are variable. Please reference Attribute Control Chart Toolset for more information.
In which stage of a Six Sigma DMAIC project are hypothesis tests most frequently used? a. Define b. Measure c. Analyze d. Improve e. Control
Answer C True by common practice in application of the DMAIC process, although hypothesis testing may be used again in the Improve or Control phase to validate actions. Please reference Hypothesis Testing for more information.
Of the good habits of an effective team leader, which of the following is the most important? a. Being a motivator b. Knowing the applicable statistical methods c. Setting a positive example of how you want the team to cooperate d. Making certain the team members stay in their respective areas of expertise e. Assuring meetings start on time
Answer C While failure to deliver any of the options can undermine team success, serving as a role model supports all aspects of leading the team. Please reference Improving Team Development for more information.
At which step of the measurement flow chart is a Measurement System Analysis (Gauge R&R) study performed? a. Identify what to measure b. Determine how to measure c. Develop sampling and reaction plan d. Validate measurement system e. Add to control plan
Answer D Please reference Measurement As A Process for more information.
Which of the following characteristics should a data sample always have? a. The data are selected periodically (in time order). b. The data are selected randomly. c. The data reasonably represent the range of output being sampled. d. All of the above. e. None of the above.
Answer D A good data sample should include observations from different points in time, selected with equal probability for all items at that point in time and should reasonably cover the range of output at that point in time. Please reference Collecting Data for more information.
A Lean Six Sigma team is working to reduce the set-up time for an operating room at a hospital. All set-up activities have been identified and categorized. What is the best next step? a. Move Internal Set-up Activites to Preventive Set-up b. Move External Set-up Activites to Internal Set-up c. Move Running Set-up Activites to Shut-down Set-up d. Move Internal Set-up Activites to External Set-up e. Move External Set-up Activites to Running Set-up
Answer D By undertaking as many set-up activities as possible when the process is running (External Setup), process downtime is minimized during changeover. Please reference Quick Changeover Toolset for more information.
A process has an output of 270 defects in 5400 units. Each product goes through 8 steps, with one defect opportunity at each step. What is the sigma level of the process? a. 3.1 b. 5.3 c. 2.7 d. 4.0 e. 4.9
Answer D DPMO is (270/(5400*8))*1,000,000 = 6,250. See the Six Sigma Calculator Please reference Calculating the Sigma Level - Toolset for more information.
When concluding a Six Sigma project, when the team moves on and the process owner resumes control of the improved process, which of the following is NOT a key deliverable of the team? a. Control plan and updated documents for the process b. On-going measures of performance c. Sharing lessons learned during the project d. Permanent team member assigned to the process e. Operating ranges for key variables
Answer D Establishing and documenting a sustainable control plan includes on-going measures of performance, lessons learned and operating ranges of key variables. These deliverables, and adherence to the plan, ensure sustaining the improvements gained without requiring on-going staffing by the Six Sigma team. Please reference Ending the Project for more information.
A Lean Six Sigma team working within the admissions department of a university wants to calculate the average cycle time to process an application during the peak admissions season. The team knows that there are 2,760 applications in process, and that the current staff can process 41 per day. Using Little's Law, what is the cycle time in days? a. 45 b. 51 c. 58 d. 67 e. 73
Answer D Little's Law tells us that cycle time = Things In Process / Processing Rate = 2760/41 = 67.32, rounded to 67. Please reference Continuous Flow Toolset for more information.
A Lean Six Sigma Team wants to create a process map that will show the geographic movement of a unit through the process, along with the distance travelled through the various steps. What type of process map would be most appropriate? a. SIPOC Map b. Deployment Flow Chart c. Value-Added Flow Chart d. Spaghetti Diagram e. Value Stream Map
Answer D SIPOC maps show key inputs and outputs, by stage. Deployment Flow Charts show who is repsponsible for each step. Value-Added Flow Charts break down value-added and non-value-added operations. Value Stream Maps show the flow of material, but are more focused on processing time, set-ups, and inventories. Please reference Spaghetti Charts for more information.
135.610 - Coorelation and Regression The regression equation of a best fit trend line is Y = 6X + 10 and the R-squared is 0.95. If the independent variable is set at 5 what is the expected value of the dependent variable? a. 6 b. 10 c. 30 d. 40 e. 56
Answer D Solve equation for Y = 6x5 + 10 = 40 Please reference Multiple Regression Toolset for more information.
A "Thought Process Map" can be used at any stage of a Six Sigma project. Which of these steps is NOT included in a Thought Process Map? a. Action b. Answer c. Question d. Analyze
Answer D The 3 steps of a Thought Process Map are: Question, Action, Answer. Analysis takes place throughout the process. Please reference Process Mapping Practice Questions for more information.
Which of the following tools is most frequently used in brainstorming? a. Pareto diagram b. Pugh matrix c. Corrective action matrix d. Affinity diagram e. Thought process map
Answer D The affinity diagram is often used to organize and categorize the output of a brainstorming event. Please reference Brainstorming for more information.
If a measurement system is constantly off by a certain amount, how would the problem be characterized? a Precision b. Repeatibility c. Reproducibility d. Bias e. Linearity
Answer D This is true by definition. Bias is generally related to the calibration of the measurement system. Please reference The Analysis of Measurement Systems for more information.
You are the controller for the large hospital supply company. The Six Sigma project team working on reducing the accounts receivable cycle time has completed the project and wants to meet with you to sign the Project Close-Out template shown below. Based on the information shown, would you sign the Project Close-Out document or would you require additional information? a. Sign the document, everything is in order. b. More information on the project description is needed. c. More information on the specific improvement actions is needed. d. More specific information on how the requirement is measured is needed. e. More information on the target and value is needed.
Answer D While it may be well understood within the organization as to the make-up of the "days outstanding" measure; it's a good idea to provide that information here just to make sure everyone understands. For example, is it the AVERAGE number of days for all Class I invoices or the MAXIMUM number of days for any one Class I invoice? This should be stated in the description of how the requirement is measured. Please reference Ending the Project for more information.
A mortgage company tracks loan application cycle time. Below is a histogram of a recent data sample collected from three randomly chosen loan officers. Note the skewed pattern. Which of the following actions should be taken next? a. Do nothing. b. Increase the number of histogram bins to see if a meaningful pattern emerges. c. Use a box plot to identify any outliers. d. See if the process is in control by plotting the data on an X and Moving Range chart. e. Stratify and re-plot the data to see if there are any underlying patterns.
Answer E It may be useful to stratify the data in order to see underlying patterns that can help locate the source of variation. Note the three separate modes found when the data was stratified by loan officer. Please reference Histogram Toolset for more information.
This question refers to the "Claims Processing" case. A hospital processes claims and the insurance companies often reject them for coding errors. A Six Sigma team has been working on a project to reduce coding errors for the past 15 months and the data for the number and type of coding errors can be downloaded above in the "ClaimCoding" file. Use this data to answer the question below. Assuming that each claim has 20 opportunities for errors, what is the sigma level for coding errors in months 1 and 15? a. Month 1=4.7 sigma level, Month 15 = 3.3 b. Month 1=3.0 sigma level, Month 15 = 2.7 c. Month 1=4.7 sigma level, Month 15 = 3.7 d. Month 1=3.0 sigma level, Month 15 = 3.8 e. Month 1=3.0 sigma level, Month 15 = 3.3
Answer E M1 DPMO=(868x1,000,000)/(716X20); M15 PMO=(605x1,000,000)/(788X20). See Sigma Level calculator for corresponding Sigma Level. Please reference Calculating the Sigma Level - Toolset for more information.
For project selection, which of the following is NOT a key input? a. Costs related to the project b. Capital required c. Likelihood of success d. Effect on customer e. Popularity among team members
Answer E Project selection should be driven by facts, not opinions. Please reference Project Selection Toolset for more information.
If your data represents % defective and you have daily samples, the size of which, although large (>50), varies from day to day, which control chart should you use? a. X-bar & R chart b. c Chart c. np Chart d. u Chart e. p Chart
Answer E The p chart is used for percent defective. You could also use an XmR Chart (ImR Chart). Please reference SPC Chart Selection for more information.
On an SPC chart (control chart), the differences between subgroups that are WITHIN the control limits are due to: a. Operator tampering b. Assignable cause variation c. Out of control conditions d. Special cause variation e. Common cause variation
Answer E Variation between subgroups is noise or sampling error, called common cause variation. Please reference SPC - Control Chart Limits for more information.
Which of the following activities is NOT an example of visual control at a work station? a. Posted performance measurements b. Removal of unnecessary clutter - unused documents and equipment c. Removal of visual barriers, such as storage racks or unnecessary walls or funiture d. Quality standards on visible display e. Motivational signs and posters
Answer E Visual Control refers to a collection of communication and organization strategies used to promote quick visual exchange of information on the shop floor or within an office environment. Please reference Visual Control for more information.