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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. PFMEA
Before production starts
Rapid improvement process.
Supplier - input - process - output - customer.
Walter A. Shewhart

2. An SPC chart shows no points outside the control limits. Does this mean the process is in control?
The target number of standard deviations from the mean for specifications.
No -- the variation also has to be random and "expected."
What the value of the dependent variable is when the independent variable is zero.
The Japanese national quality award.

3. Process check sheets
Method developed by Ishikawa to graphically display the causes of any given problem
Stratify a particular defect type according to logical criteria
To be a member of a Six Sigma project team.
Used to create frequency distribution tally sheets

4. What graphical tool is used to show the relationship between two numerical variables?
A scatterplot.
Define - measure - analyze - improve - control.
1) Obtain Residuals 2) Fill out table --> y coordinates: F = 100 (i-.5)/N x coordinates: Ordered Residual 3) Plot on Normal Probability Paper
Sort - Set in Order - Shine - Standardize - Sustain

5. Define product reliability.
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
Mean time to failure.
Through producer/consumer negotiation.
Studying firms with the best performance in a particular area.

6. Regression
Workers - machines - materials.
Represents the behavior of a process
They move closer to the center line.
Not necessarily.

7. If your process is capable at two sigma - what percentage of the output will you have to inspect to find defectives?
What the value of the dependent variable is when the independent variable is zero.
100%
A brainstorming tool that shows the connections between ideas.
Rapid improvement process.

8. In Juran's Cost of Quality model - which categories of costs balance which other categories?
Prevention and appraisal costs are balanced against internal and external failure.
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).
A random variable that summarizes the information from the sample(s).
If the Response vs. Levels graph if the response lines are not parallel (crossing)

9. FMEA
It looks to minimize the probability of a failure - or to minimize its effects
Fractional factorial designs (orthogonal arrays)
Is what induces the failure
Variable.

10. Daniel Test
Causes that lead to a particular effect.
Prevention - appraisal - internal failure - external failure.
Represent the errors which are random variables with an assumed normal distribution with mean zero and a constant variance σ2.
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:

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

12. In a regression - what does R-square tell you?
The amount of variation in the dependent variable that is explained by the variation in the independent variable(s).
Incoming materials inspection - inspection and testing - maintaining test equipment - materials/services consumed
X-bar-bar
Variable.

13. Residual
The degree to which a product meets pre-established standards.
To manage the Six Sigma project.
Represent the errors which are random variables with an assumed normal distribution with mean zero and a constant variance σ2.
Defects Per Million Opportunities

14. What is the center line of an X-bar chart?
Not necessarily.
Complaint adjustment - returned material - warranty charges - allowances - loss of future business.
X-bar-bar
Represents the behavior of a process

15. When either attribute or variable measures could be used for SPC - why might attribute measurement be preferred?
Can't tell without a Range chart.
The process of ranking opportunities to determine which of many potential opportunities should be pursued first.
5%
Lower skill requirements - faster - less chance for error.

16. Definition of Interaction
QFD
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
Someone who is consistently against virtually everything.
An interaction is defined as a dependence relationship between the response and the levels of two or more variables

17. DOE
An experiment where one or more variables believed to have an effect on an experimental outcome are identified and manipulated according to a plan
Attribute
It's good -- but it's still out of control!
A tool that shows performance along key dimensions all at once.

18. What is the Deming Prize?
Large enough to find two of the attribute - on average.
They move closer to the center line.
It looks to minimize the probability of a failure - or to minimize its effects
The Japanese national quality award.

19. If a three-stage process has 90% yields at each stage - what is the overall yield?
0.9^3 or 72.9%
Data reduction to put a large number of qualitative inputs into a smaller number of major dimensions
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).
The target number of standard deviations from the mean for specifications.

20. Uses of regression
The Japanese national quality award.
Conformance to specifications.
Prediction and estimation. based on an unknown x value - estimation is based on a known x value
Mean time to replacement.

21. Creating a Run Chart
The process of ranking opportunities to determine which of many potential opportunities should be pursued first.
It looks to minimize the probability of a failure - or to minimize its effects
Quality planning - design review - education and training - process control - IS costs - quality reporting - improvement project costs - working with suppliers before production.
1) Plot a Line chart of the data in time sequence 2) Draw a line at the median

22. Approximately what percent of a normal distribution falls between ± 2 standard deviations from the mean?
Supplier - input - process - output - customer.
95%
100%
A descending order-sorted bar chart with a cumulative percentage line.

23. What is the difference between the way sampling is done for SPC and for acceptance sampling?
Waste.
Fitness for use.
Sampling for SPC is done real time.
Organize ideas into meaningful categories by recognizing their underlying similarity

24. Which quality guru developed the concept of loss to society?
Observed variation in response is caused by the input
Brand image.
Taguchi
Define - measure - analyze - improve - control.

25. In a Z table - what is Z?
A tool that shows the physical flows through a space.
The manager in charge of a process being improved in a Six Sigma project.
The number of standard deviations some value is from the mean.
The primary operating characteristics of a product.

26. What is the formula for standard deviation?
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 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).
Complaint adjustment - returned material - warranty charges - allowances - loss of future business.
=sqrt(Σ(x-x-bar)^2)/(n-1))

27. Define serviceability.
If the Response vs. Levels graph if the response lines are not parallel (crossing)
Used to create frequency distribution tally sheets
95%
Speed - courtesy - competence - and ease of repair.

28. ANOVA

29. Does it ever make sense to accept a job when a process is incapable?
Workers - machines - materials.
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
10 if Almost impossible to detect
They move closer to the center line.

30. Where should specifications fall in relation to ± 3 sigma for the process in order for a process to be capable.
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.
The ratio of outputs to inputs; 1-scrap.
Outside.
To do a capability study for a non-centered process.

31. Effect ranking (Severity of the Defect)
The US national quality award.
10 for Hazardous without warning 1 for none
To mentor/coach (and sometimes train) black belts.
The target number of standard deviations from the mean for specifications.

32. For what is a p-chart used?
Large enough to find two of the attribute - on average.
F_alpha - df(tr) - df (error)
No -- the variation also has to be random and "expected."
To monitor a process when measurement by attribute is used.

33. List two components of internal failure.
The cycle time required to meet demand.
5%
The target number of standard deviations from the mean for specifications.
Scrap - rework - retest - downtime - yield losses - disposition costs.

34. What is the role of a green belt?
Central Limit Theorem
1) Obtain Residuals 2) Fill out table --> y coordinates: F = 100 (i-.5)/N x coordinates: Ordered Residual 3) Plot on Normal Probability Paper
Observed variation in response is caused by the input
To be a member of a Six Sigma project team.

35. What is a Gantt chart?
Shows the temporal flow of activities in a project network.
X-bar-bar
Concluding there has been an effect/change when there has not.
Actual drawings - layouts - maps - etc which show where a defect occurs

36. What is DPMO?
The Japanese national quality award.
A diagram that shows the relationships between activities in a project network.
Workers - machines - materials.
Defects Per Million Opportunities

37. What are the three main categories of assignable cause?
Workers - machines - materials.
A scatterplot.
The process of ranking opportunities to determine which of many potential opportunities should be pursued first.
Failure Modes and Effects Analysis

38. What inventory approach contributes to process quality by "lowering the river to find the rocks?"
The House of Quality.
Blame.
Lean (or JIT).
Is what induces the failure

39. Defect location check sheets
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).
Actual drawings - layouts - maps - etc which show where a defect occurs
Someone who is consistently against virtually everything.
Blame.

40. Define performance quality.
The primary operating characteristics of a product.
0.9^3 or 72.9%
Decomposing the total variation of data into: (a) the internal or "natural" or "within" groups variation - and (b) the "between" groups variation in such a way that when these two types of variation are compared - it's possible to determine if there
= yij - y(bar)i --> value minus sum of that treatment (of row)

41. What is a spaghetti diagram?
A tool that shows the physical flows through a space.
Brand image.
No -- only if the process is also capable.
Walter A. Shewhart

42. Why do you need two control charts for variables SPC?
Attribute
Because the mean and standard deviation are independent of each other.
Variable.
Concluding there has been an effect/change when there has not.

43. If you can only collect categorical data - what type of SPC charting can you do?
=sqrt((p*(1-p)/n)
Linearity - normality - homoscedasticity - independence.
Critical to quality.
Attribute.

44. DFMEA
Initiated before or at design concept finalization
Because the mean and standard deviation are independent of each other.
Shifts - Trends - Repeating patterns - Correlation with known events
5%

45. What is an affinity diagram?
Financial - customer - internal process - innovation and learning.
Sampling for SPC is done real time.
No; if the process is centered - Cp will be the same; if not - Cpk is what you need to determine capabilty.
A brainstorming tool that shows the connections between ideas.

46. In a regression - what does the coefficient of the intercept tell you
The number of standard deviations some value is from the mean.
What the value of the dependent variable is when the independent variable is zero.
Organize ideas into meaningful categories by recognizing their underlying similarity
= S x O x D S--> Severity O--> Occurrence D--> Detection Higher the number the worse it is

47. Complete this quality phrase: 'Fix the process - not the _____.'
Pleasing to the senses.
Blame.
Before production starts
A tool that shows where there is waste in a process.

48. What is the center line of a p-chart?
Fishbone - cause-and-effect diagram.
Not necessarily.
Look to your customer - not to other firms. "You can always find someone shorter - fatter and balder!"
p-bar - the long-run percent defective.

49. When Crosby said - "Quality is free -" what dimension of quality was he referring to?
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
1) Obtain Residuals 2) Fill out table --> y coordinates: F = 100 (i-.5)/N x coordinates: Ordered Residual 3) Plot on Normal Probability Paper
Conformance to specifications.
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).

50. What is the difference between Lean and Six Sigma?
Lean is waste reduction - Six Sigma is variation reduction.
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
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).
The degree to which a product meets pre-established standards.