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Six Sigma

Subjects : certifications, six-sigma, business-skills

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. If a three-stage process has 90% yields at each stage - what is the overall yield?
Brand image.
0.9^3 or 72.9%
=sqrt(Σ(x-x-bar)^2)/(n-1))
No; if the process is centered - Cp will be the same; if not - Cpk is what you need to determine capabilty.

2. Regression Analysis
QFD
Prevention and appraisal costs are balanced against internal and external failure.
Technique used to relate through a model - one or more independent variables and a dependent variable (response)
The amount of variation in the dependent variable that is explained by the variation in the independent variable(s).

3. Non-random patterns (Run Charts)
A tool that shows the physical flows through a space.
Because the mean and standard deviation are independent of each other.
To monitor a process when measurement by variables is used.
Shifts - Trends - Repeating patterns - Correlation with known events

4. There are two milling machines in the shop. Data has been collected on one to compute control limits for both. This is acceptable SPC practice - true or false and why?
Outside.
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
Conformance to specifications.
False - because each machine will have different natural tolerances.

5. Define serviceability.
Speed - courtesy - competence - and ease of repair.
Incoming materials inspection - inspection and testing - maintaining test equipment - materials/services consumed
QFD
The Japanese national quality award.

6. What is the Baldrige Award?
If the Response vs. Levels graph if the response lines are not parallel (crossing)
To monitor a process when measurement by variables is used.
The US national quality award.
Producer risk.

7. The data points on an SPC p-chart of defective percent plot below the mean. Is this good or bad?

8. In Juran's Cost of Quality model - which categories of costs balance which other categories?
Lean (or JIT).
A tool that shows the physical flows through a space.
The gap between what is promised and what is delivered.
Prevention and appraisal costs are balanced against internal and external failure.

9. What does DMAIC stand for?
Define - measure - analyze - improve - control.
10 if Almost impossible to detect
Before production starts
0.9^3 or 72.9%

10. List Garvin's eight dimensions of product quality.
Organize ideas into meaningful categories by recognizing their underlying similarity
Performance - features - conformance - reliability - durability - serviceability - aesthetics - perceived quality
Consumer risk.
Reliability - Assurance - Responsiveness - Tangibles - Empathy

11. Does it ever make sense to accept a job when a process is incapable?
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
Attribute
F_alpha - df(tr) - df (error)
50%

12. What is a run chart?
Deming.
A time series plot.
QFD
Workers - machines - materials.

13. Approximately what percent of a normal distribution falls between ± 1 standard deviations from the mean?
Mean time to failure.
Variable.
A chart that breaks the range of data into equal intervals and then shows the count of occurrences in each interval.
68%

14. What is the 5S model?
To manage the Six Sigma project.
System to reduce waste and optimize productivity through maintaining an orderly workplace and using visual cues to achieve more consistent operational results.
Organize ideas into meaningful categories by recognizing their underlying similarity
Fishbone - cause-and-effect diagram.

15. Effect ranking (Severity of the Defect)
To do a capability study for a non-centered process.
Deming.
10 for Hazardous without warning 1 for none
Technique used to relate through a model - one or more independent variables and a dependent variable (response)

16. Regression
Critical to quality.
Represents the behavior of a process
The amount of variation in the dependent variable that is explained by the variation in the independent variable(s).
An assertion or conjecture concerning one or more populations

17. How does Juran define quality?
Mistake-proofing.
A simple graph between two variables - visualize the type - degree of strength and shape of the relationship between two variables
Fitness for use.
Technical quality is the "what" of the service; functional quality is the "how."

18. What does the abbreviation UCL stand for?
Variable.
Performance - features - conformance - reliability - durability - serviceability - aesthetics - perceived quality
Vary two or more variables simultaneously - Multiple measurements are obtained under the same experimental conditions
Upper control limit.

19. Risk Priority Number RPN
An interaction is defined as a dependence relationship between the response and the levels of two or more variables
Prediction and estimation. based on an unknown x value - estimation is based on a known x value
Attribute.
= S x O x D S--> Severity O--> Occurrence D--> Detection Higher the number the worse it is

20. Advantages of DOE
Hold all input variables constant except one. Observe the response as you vary the single input.
Lean (or JIT).
10 for Hazardous without warning 1 for none
1.Interactions can be detected and measured 2.Each value does the work of several values 3.Experimental error is quantified and used to determine the confidence the experimenter has in the conclusions

21. What is DMADV?
How much variance you expect around the prediction; two SEs gives you a 95% confidence interval.
The degree to which a product meets pre-established standards.
Define - measure - analyze - design - verify.
It usually isn't possible to hold all other variables constant - There is no way to account for the effect of joint variation of independent variables - such as interaction - There is no way to account for experimental error - including measurement v

22. Your production process meets customer specifications. Is your process in control?
Blame.
Not necessarily.
Scrap - rework - retest - downtime - yield losses - disposition costs.
Can't tell without a Range chart.

23. You have been plotting sample means on an x-bar chart and all points indicate normal - expected variation. Is the process in control?

24. How are LQL and AQL determined in an acceptance sampling plan?
Because the mean and standard deviation are independent of each other.
The House of Quality.
Through producer/consumer negotiation.
Scrap - rework - retest - downtime - yield losses - disposition costs.

25. Uses of regression - Control
How much variance you expect around the prediction; two SEs gives you a 95% confidence interval.
Fewer good units to sell - increased variable cost/unit.
They move closer to the center line.
To obtain a certain desirable outcome from the process

26. Residual(eij)
= yij - y(bar)i --> value minus sum of that treatment (of row)
Kaoru Ishikawa.
Define - measure - analyze - improve - control.
To do a capability study for a non-centered process.

27. One factor at a time (OFAT)
Observed variation in response is caused by the input
Central Limit Theorem
1) Identify the Range (Max Value - Min Value) 2) Determine # of bins 3) Determine the Width of each bin --> (Range / # Bins) 4) Put values in correct Bin
Fractional factorial designs (orthogonal arrays)

28. What is process capability?
The ability of a process to consistently meet customer specifications.
An experiment where one or more variables believed to have an effect on an experimental outcome are identified and manipulated according to a plan
A time series plot.
QFD

29. Define yield.
The ratio of outputs to inputs; 1-scrap.
A descending order-sorted bar chart with a cumulative percentage line.
3.4 (assuming 1.5 sigma shift in the mean)
A brainstorming tool that shows the connections between ideas.

30. In the Service Quality Gap Model - what is Gap 5?
Shows the temporal flow of activities in a project network.
Complaint adjustment - returned material - warranty charges - allowances - loss of future business.
The gap between what customers expect and the service they receive.
Another way to assess the significance of the analyzed factors is through a graphic procedure developed by C. Daniel when only one replicate (a single observation) was obtained:

31. List two components of internal failure.
A systemized group of activities designed to 1. recognize and evaluate the potential failure of product/process and its effects 2. Identify actions which could eliminate or reduce the chance of potential failure ocurring 3. document the process
Plot the residuals vs. the fitted values (mean of each group - y(hat) = y (bar)i ) - Assumption of ____________not rejected if the dispersion of every group is approximately the same.
Scrap - rework - retest - downtime - yield losses - disposition costs.
The gap between what is promised and what is delivered.

32. What is an affinity diagram?
0.9^3 or 72.9%
A diagram that shows the relationships between activities in a project network.
Lean (or JIT).
A brainstorming tool that shows the connections between ideas.

33. A process is operating "in control." Does this mean the customer's requirements are met?
Variable.
No -- only if the process is also capable.
Technique used to relate through a model - one or more independent variables and a dependent variable (response)
Large enough to find two of the attribute - on average.

34. What is a Gantt chart?
Shows the temporal flow of activities in a project network.
The amount of variation in the dependent variable that is explained by the variation in the independent variable(s).
Critical to quality.
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.

35. List two components of prevention cost.
The amount of variation in the dependent variable that is explained by the variation in the independent variable(s).
Plot the residuals vs. the fitted values (mean of each group - y(hat) = y (bar)i ) - Assumption of ____________not rejected if the dispersion of every group is approximately the same.
Quality planning - design review - education and training - process control - IS costs - quality reporting - improvement project costs - working with suppliers before production.
Technique used to relate through a model - one or more independent variables and a dependent variable (response)

36. Defect check sheets
Define - measure - analyze - improve - control.
The manager in charge of a process being improved in a Six Sigma project.
Controlling quality at the source.
Different types of defects are listed (used for Pareto chart)

37. When is Cpk used?
To do a capability study for a non-centered process.
Rapid improvement process.
A descending order-sorted bar chart with a cumulative percentage line.
A time series plot.

38. In a Z table - what is Z?
Can't tell without a Range chart.
Studying firms with the best performance in a particular area.
The number of standard deviations some value is from the mean.
Concluding there has been an effect/change when there has not.

39. Explain the difference between technical and functional service quality.
Technical quality is the "what" of the service; functional quality is the "how."
The cycle time required to meet demand.
Failure Modes and Effects Analysis
Fewer good units to sell - increased variable cost/unit.

40. What is FMEA?
Failure Modes and Effects Analysis
= S x O x D S--> Severity O--> Occurrence D--> Detection Higher the number the worse it is
To obtain a certain desirable outcome from the process
Concluding there has been an effect/change when there has not.

41. What is a histogram?
A chart that breaks the range of data into equal intervals and then shows the count of occurrences in each interval.
An experiment where one or more variables believed to have an effect on an experimental outcome are identified and manipulated according to a plan
Through producer/consumer negotiation.
Represent the errors which are random variables with an assumed normal distribution with mean zero and a constant variance σ2.

42. Why do you need two control charts for variables SPC?
Speed - courtesy - competence - and ease of repair.
consists of plotting the residuals vs. the order of each experiment - If - as in the case of the constant variance a random horizontal band is obtained - the ______________ of the residuals is not rejected. (should be random above a below the line i
Because the mean and standard deviation are independent of each other.
Fractional factorial designs (orthogonal arrays)

43. For what is an x-bar chart used?
68%
5%
Different types of defects are listed (used for Pareto chart)
To monitor a process when measurement by variables is used.

44. What are two other names for an Ishikawa diagram?
Lean is waste reduction - Six Sigma is variation reduction.
To be a member of a Six Sigma project team.
Fishbone - cause-and-effect diagram.
The manager in charge of a process being improved in a Six Sigma project.

45. What is CTQ?
Critical to quality.
Producer risk.
Stratify a particular defect type according to logical criteria
Complaint adjustment - returned material - warranty charges - allowances - loss of future business.

46. Detection Criteria Ranking
The process of ranking opportunities to determine which of many potential opportunities should be pursued first.
10 if Almost impossible to detect
F_alpha - df(tr) - df (error)
No -- only if the process is also capable.

47. What is muda
Concluding there has not been an effect/change when there has.
Waste.
1) Obtain Residuals 2) Fill out table --> y coordinates: F = 100 (i-.5)/N x coordinates: Ordered Residual 3) Plot on Normal Probability Paper
Producer risk.

48. FMEA
Actual drawings - layouts - maps - etc which show where a defect occurs
False - because each machine will have different natural tolerances.
Attribute.
A systemized group of activities designed to 1. recognize and evaluate the potential failure of product/process and its effects 2. Identify actions which could eliminate or reduce the chance of potential failure ocurring 3. document the process

49. FMEA
It looks to minimize the probability of a failure - or to minimize its effects
Taguchi
3.4 (assuming 1.5 sigma shift in the mean)
Actual drawings - layouts - maps - etc which show where a defect occurs

50. What is a Gage R&R?
Studying firms with the best performance in a particular area.
Prediction and estimation. based on an unknown x value - estimation is based on a known x value
A tools that is used to measure the amount of variation in the measurement system arising from the measurement device (repeatability) and the people taking the measurement (reproducibility).
A simple graph between two variables - visualize the type - degree of strength and shape of the relationship between two variables