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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. What is a spaghetti diagram?
Fractional factorial designs (orthogonal arrays)
A tool that shows the physical flows through a space.
Prediction and estimation. based on an unknown x value - estimation is based on a known x value
Lower control limit.

2. Define durability.
Mean time to replacement.
Conformance to specifications.
To do a capability study for a non-centered process.
Taguchi

3. Effect ranking (Severity of the Defect)
Scrap - rework - retest - downtime - yield losses - disposition costs.
10 for Hazardous without warning 1 for none
Represent the errors which are random variables with an assumed normal distribution with mean zero and a constant variance σ2.
Assigns scores to weighted criteria for each project under consideration.

4. Regression
An experiment where one or more variables believed to have an effect on an experimental outcome are identified and manipulated according to a plan
No -- if it is not the same - it can only be worse!
Central Limit Theorem
Represents the behavior of a process

5. What is Kaizen?
Rapid improvement process.
Method developed by Ishikawa to graphically display the causes of any given problem
Lower skill requirements - faster - less chance for error.
Is the consequence of the failure.

6. Test for constant variance
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.
Large enough to find two of the attribute - on average.
The gap between what management thinks customers want and what customers really want.
3.4 (assuming 1.5 sigma shift in the mean)

7. Based on what principal can we use the normal distribution assumptions for SPC?
Central Limit Theorem
To do a capability study for a non-centered process.
Upper control limit.
Rank of 10 if there is >= 100 per 1000 piece Rank of 1 if there is <=.01 per 1000 pieces

8. List two components of external failure.
Prevention and appraisal costs are balanced against internal and external failure.
The process of ranking opportunities to determine which of many potential opportunities should be pursued first.
Complaint adjustment - returned material - warranty charges - allowances - loss of future business.
The primary operating characteristics of a product.

9. What is written on the "spines" of a fishbone diagram?
3.4 (assuming 1.5 sigma shift in the mean)
Technical quality is the "what" of the service; functional quality is the "how."
The gap between specifications and how service is performed.
Causes that lead to a particular effect.

10. F value
The number of standard deviations some value is from the mean.
A tool that shows where there is waste in a process.
F_alpha - df(tr) - df (error)
Look to your customer - not to other firms. "You can always find someone shorter - fatter and balder!"

11. In Juran's Cost of Quality model - which categories of costs balance which other categories?
False - because each machine will have different natural tolerances.
= yij - y(bar)i --> value minus sum of that treatment (of row)
Prevention and appraisal costs are balanced against internal and external failure.
QFD

12. What is the formula for the standard deviation of a proportion?
3.4 (assuming 1.5 sigma shift in the mean)
=sqrt((p*(1-p)/n)
To monitor a process when measurement by attribute is used.
Assigns scores to weighted criteria for each project under consideration.

13. What is Type II Error?
Large enough to find two of the attribute - on average.
A descending order-sorted bar chart with a cumulative percentage line.
Concluding there has not been an effect/change when there has.
Shifts - Trends - Repeating patterns - Correlation with known events

14. What are the four categories of costs in Juran's framework?
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
Prevention - appraisal - internal failure - external failure.
Fitness for use.
No -- only if the process is also capable.

15. Cause and Effect Diagrams
The gap between what management thinks customers want and the process 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
Method developed by Ishikawa to graphically display the causes of any given problem
Supplier - input - process - output - customer.

16. What is the 5S model?
System to reduce waste and optimize productivity through maintaining an orderly workplace and using visual cues to achieve more consistent operational results.
3.4 (assuming 1.5 sigma shift in the mean)
Mean time to replacement.
Large enough to find two of the attribute - on average.

17. What are two other names for an Ishikawa diagram?
= yij - y(bar)i --> value minus sum of that treatment (of row)
The House of Quality.
Fishbone - cause-and-effect diagram.
Define - measure - analyze - improve - control.

18. What is Jidoka?
A simple graph between two variables - visualize the type - degree of strength and shape of the relationship between two variables
Lean is waste reduction - Six Sigma is variation reduction.
Assigns scores to weighted criteria for each project under consideration.
Controlling quality at the source.

19. When is Cpk used?
= S x O x D S--> Severity O--> Occurrence D--> Detection Higher the number the worse it is
To do a capability study for a non-centered process.
Mean time to replacement.
Conformance to specifications.

20. With Six Sigma capability - how many defects per million opportunities would you see?
Look for the assignable cause of non-random variation.
3.4 (assuming 1.5 sigma shift in the mean)
A brainstorming tool that shows the connections between ideas.
Complaint adjustment - returned material - warranty charges - allowances - loss of future business.

21. Design of Experiments (DOE) approach
Vary two or more variables simultaneously - Multiple measurements are obtained under the same experimental conditions
Sampling for SPC is done real time.
Look to your customer - not to other firms. "You can always find someone shorter - fatter and balder!"
False - because each machine will have different natural tolerances.

22. What is FMEA?
Technical quality is the "what" of the service; functional quality is the "how."
Failure Modes and Effects Analysis
Quality planning - design review - education and training - process control - IS costs - quality reporting - improvement project costs - working with suppliers before production.
Workers - machines - materials.

23. Define product reliability.
Rank of 10 if there is >= 100 per 1000 piece Rank of 1 if there is <=.01 per 1000 pieces
Brand image.
Mean time to failure.
Taguchi

24. Creating a Run Chart
1) Plot a Line chart of the data in time sequence 2) Draw a line at the median
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
A brainstorming tool that shows the connections between ideas.
Actual drawings - layouts - maps - etc which show where a defect occurs

25. Manual Test for Nomality
Initiated before or at design concept finalization
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.
Conformance to specifications.

26. An SPC chart shows no points outside the control limits. Does this mean the process is in control?
Before production starts
No -- the variation also has to be random and "expected."
If the Response vs. Levels graph if the response lines are not parallel (crossing)
Attribute.

27. Which type of SPC measurement is more precise - variable or attribute?
The secondary characteristics of a product; "bells and whistles."
Variable.
Deming.
Pleasing to the senses.

28. If a three-stage process has 90% yields at each stage - what is the overall yield?
Mean time to failure.
The Japanese national quality award.
= S x O x D S--> Severity O--> Occurrence D--> Detection Higher the number the worse it is
0.9^3 or 72.9%

29. Stratified defect check sheets
If the Response vs. Levels graph if the response lines are not parallel (crossing)
The manager in charge of a process being improved in a Six Sigma project.
How likely it is to have an F statistic of that value if there really is no relationship between the dependent variable and the independent variable(s).
Stratify a particular defect type according to logical criteria

30. What is Little's Law?
Is the way in which the failure is manifested.
Central Limit Theorem
=sqrt(Σ(x-x-bar)^2)/(n-1))
Inventory = throughput x flow time.

31. For what is an x-bar chart used?
The target number of standard deviations from the mean for specifications.
Lower control limit.
A time series plot.
To monitor a process when measurement by variables is used.

32. What is a Pareto chart?
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:
A tool that shows the physical flows through a space.
Fishbone - cause-and-effect diagram.
A descending order-sorted bar chart with a cumulative percentage line.

33. Define performance quality.
The primary operating characteristics of a product.
Large enough to find two of the attribute - on average.
A tool that shows where there is waste in a process.
Method developed by Ishikawa to graphically display the causes of any given problem

34. Define serviceability.
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
Mean time to failure.
Central Limit Theorem
Speed - courtesy - competence - and ease of repair.

35. In a Z table - what is Z?
Pleasing to the senses.
A tool that shows the physical flows through a space.
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
The number of standard deviations some value is from the mean.

36. Failure Mode
Critical to quality.
Fractional factorial designs (orthogonal arrays)
Is the way in which the failure is manifested.
Performance - features - conformance - reliability - durability - serviceability - aesthetics - perceived quality

37. Taguchi's experimental designs are of this type.
No -- only if the process is also capable.
Organize ideas into meaningful categories by recognizing their underlying similarity
Fractional factorial designs (orthogonal arrays)
Is what induces the failure

38. If your process is capable at two sigma - what percentage of the output will be defective (assuming the process is in control)?
Workers - machines - materials.
Attribute
5%
Organize ideas into meaningful categories by recognizing their underlying similarity

39. Definition of Interaction
No -- if it is not the same - it can only be worse!
Upper control limit.
The ratio of outputs to inputs; 1-scrap.
An interaction is defined as a dependence relationship between the response and the levels of two or more variables

40. How does Juran define quality?
To obtain a certain desirable outcome from the process
Fitness for use.
Different types of defects are listed (used for Pareto chart)
The secondary characteristics of a product; "bells and whistles."

41. Pareto Analysis
Define - measure - analyze - improve - control.
The process of ranking opportunities to determine which of many potential opportunities should be pursued first.
Mean time to failure.
They move closer to the center line.

42. The Test Statistic (TS)
A random variable that summarizes the information from the sample(s).
Complaint adjustment - returned material - warranty charges - allowances - loss of future business.
Speed - courtesy - competence - and ease of repair.
They move closer to the center line.

43. Failure cause
Different types of defects are listed (used for Pareto chart)
Complaint adjustment - returned material - warranty charges - allowances - loss of future business.
A simple graph between two variables - visualize the type - degree of strength and shape of the relationship between two variables
Is what induces the failure

44. What is the role of a master black belt?
To mentor/coach (and sometimes train) black belts.
Fewer good units to sell - increased variable cost/unit.
Mistake-proofing.
Represent the errors which are random variables with an assumed normal distribution with mean zero and a constant variance σ2.

45. List two components of prevention cost.
Quality planning - design review - education and training - process control - IS costs - quality reporting - improvement project costs - working with suppliers before production.
Failure Modes and Effects Analysis
Technique used to relate through a model - one or more independent variables and a dependent variable (response)
Performance - features - conformance - reliability - durability - serviceability - aesthetics - perceived quality

46. What is a Gantt chart?
If the Response vs. Levels graph if the response lines are not parallel (crossing)
The US national quality award.
Shows the temporal flow of activities in a project network.
Workers - machines - materials.

47. What are the three main categories of assignable cause?
Look for the assignable cause of non-random variation.
No -- the variation also has to be random and "expected."
Workers - machines - materials.
10 if Almost impossible to detect

48. Residual(eij)
QFD
= yij - y(bar)i --> value minus sum of that treatment (of row)
Method developed by Ishikawa to graphically display the causes of any given problem
An experiment where one or more variables believed to have an effect on an experimental outcome are identified and manipulated according to a plan

49. What does SIPOC stand for?
Technique used to relate through a model - one or more independent variables and a dependent variable (response)
Supplier - input - process - output - customer.
A brainstorming tool that shows the connections between ideas.
How much variance you expect around the prediction; two SEs gives you a 95% confidence interval.

50. What is CTQ?
Critical to quality.
System to reduce waste and optimize productivity through maintaining an orderly workplace and using visual cues to achieve more consistent operational results.
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.
Reliability - Assurance - Responsiveness - Tangibles - Empathy