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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. One factor at a time (OFAT)
Hold all input variables constant except one. Observe the response as you vary the single input.
Conformance to specifications.
Organize ideas into meaningful categories by recognizing their underlying similarity
50%

2. What is the center line of an X-bar chart?
X-bar-bar
The ability of a process to consistently meet customer specifications.
Before production starts
No -- if it is not the same - it can only be worse!

3. What is a network diagram?
The amount of variation in the dependent variable that is explained by the variation in the independent variable(s).
The gap between specifications and how service is performed.
A diagram that shows the relationships between activities in a project network.
95%

4. What is a histogram?
Yes - when there are opportunities to improve - when contribution margin is adequate - when achieving market share is important.
A simple graph between two variables - visualize the type - degree of strength and shape of the relationship between two variables
A chart that breaks the range of data into equal intervals and then shows the count of occurrences in each interval.
=sqrt(Σ(x-x-bar)^2)/(n-1))

5. What are the four regression assumptions?
Shifts - Trends - Repeating patterns - Correlation with known events
Variable.
Linearity - normality - homoscedasticity - independence.
A time series plot.

6. For what is a p-chart used?
Linearity - normality - homoscedasticity - independence.
The US national quality award.
To monitor a process when measurement by attribute is used.
The ratio of outputs to inputs; 1-scrap.

7. In the Service Quality Gap Model - what is Gap 1?
No -- the variation also has to be random and "expected."
Outside.
The gap between what management thinks customers want and what customers really want.
Linearity - normality - homoscedasticity - independence.

8. What is the difference between the way sampling is done for SPC and for acceptance sampling?
Method developed by Ishikawa to graphically display the causes of any given problem
Kaoru Ishikawa.
Inventory = throughput x flow time.
Sampling for SPC is done real time.

9. Why do you need two control charts for variables SPC?
The gap between what management thinks customers want and the process specifications.
Shifts - Trends - Repeating patterns - Correlation with known events
Because the mean and standard deviation are independent of each other.
Brand image.

10. 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.
Sampling for SPC is done real time.
The secondary characteristics of a product; "bells and whistles."
Rank of 10 if there is >= 100 per 1000 piece Rank of 1 if there is <=.01 per 1000 pieces

11. Histogram by Hand
The number of standard deviations some value is from the mean.
Controlling quality at the source.
10 for Hazardous without warning 1 for none
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

12. Defect check sheets
Mean time to replacement.
100%
Different types of defects are listed (used for Pareto chart)
Reliability - Assurance - Responsiveness - Tangibles - Empathy

13. Process occurance ranking
Blame.
3.4 (assuming 1.5 sigma shift in the mean)
Rank of 10 if there is >= 100 per 1000 piece Rank of 1 if there is <=.01 per 1000 pieces
Upper control limit.

14. Stratified defect check sheets
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
Stratify a particular defect type according to logical criteria
A brainstorming tool that shows the connections between ideas.
A scatterplot.

15. In a regression - what does R-square tell you?
Kaoru Ishikawa.
The amount of variation in the dependent variable that is explained by the variation in the independent variable(s).
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:
Technical quality is the "what" of the service; functional quality is the "how."

16. Approximately what percent of a normal distribution falls between ± 2 standard deviations from the mean?
No -- the variation also has to be random and "expected."
They move closer to the center line.
95%
3.4 (assuming 1.5 sigma shift in the mean)

17. What does the abbreviation UCL stand for?
5%
10 if Almost impossible to detect
Upper control limit.
1) Obtain Residuals 2) Fill out table --> y coordinates: F = 100 (i-.5)/N x coordinates: Ordered Residual 3) Plot on Normal Probability Paper

18. In a regression - what does the standard error of the estimate tell you?
=sqrt((p*(1-p)/n)
No; if the process is centered - Cp will be the same; if not - Cpk is what you need to determine capabilty.
How much variance you expect around the prediction; two SEs gives you a 95% confidence interval.
0.9^3 or 72.9%

19. Process check sheets
Controlling quality at the source.
To be a member of a Six Sigma project team.
Used to create frequency distribution tally sheets
Lower skill requirements - faster - less chance for error.

20. What percentage of a normal distribution lies above the mean?
Shifts - Trends - Repeating patterns - Correlation with known events
The ability of a process to consistently meet customer specifications.
Sampling for SPC is done real time.
50%

21. List Garvin's eight dimensions of product quality.
Linearity - normality - homoscedasticity - independence.
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
Performance - features - conformance - reliability - durability - serviceability - aesthetics - perceived quality
1) Plot a Line chart of the data in time sequence 2) Draw a line at the median

22. What is a Pareto chart?
A descending order-sorted bar chart with a cumulative percentage line.
Critical to quality.
1) Plot a Line chart of the data in time sequence 2) Draw a line at the median
Assigns scores to weighted criteria for each project under consideration.

23. What type of risk is associated with Type II Error?
Consumer risk.
A diagram that shows the relationships between activities in a project network.
Define - measure - analyze - improve - control.
Sort - Set in Order - Shine - Standardize - Sustain

24. What is Type II Error?
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.
Rank of 10 if there is >= 100 per 1000 piece Rank of 1 if there is <=.01 per 1000 pieces
Concluding there has not been an effect/change when there has.
Pleasing to the senses.

25. Define durability.
Mean time to replacement.
= S x O x D S--> Severity O--> Occurrence D--> Detection Higher the number the worse it is
Controlling quality at the source.
Central Limit Theorem

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

27. DFMEA
Initiated before or at design concept finalization
The gap between what customers expect and the service they receive.
Attribute
Shows the temporal flow of activities in a project network.

28. Your production process meets customer specifications. Is your process in control?
An assertion or conjecture concerning one or more populations
Defects Per Million Opportunities
Not necessarily.
Look for the assignable cause of non-random variation.

29. Residual(eij)
Fractional factorial designs (orthogonal arrays)
= yij - y(bar)i --> value minus sum of that treatment (of row)
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).
3.4 (assuming 1.5 sigma shift in the mean)

30. Explain the difference between technical and functional service quality.
Technical quality is the "what" of the service; functional quality is the "how."
The secondary characteristics of a product; "bells and whistles."
Walter A. Shewhart
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).

31. What are the Five Dimensions of Service Quality?
Reliability - Assurance - Responsiveness - Tangibles - Empathy
To manage the Six Sigma project.
Prediction and estimation. based on an unknown x value - estimation is based on a known x value
Fewer good units to sell - increased variable cost/unit.

32. In the Service Quality Gap Model - what is Gap 5?
The gap between what customers expect and the service they receive.
Define - measure - analyze - design - verify.
To manage the Six Sigma project.
5%

33. 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?
False - because each machine will have different natural tolerances.
How much variance you expect around the prediction; two SEs gives you a 95% confidence interval.
Brand image.
The gap between specifications and how service is performed.

34. When Crosby said - "Quality is free -" what dimension of quality was he referring to?
Conformance to specifications.
Not necessarily.
To monitor a process when measurement by variables is used.
Linearity - normality - homoscedasticity - independence.

35. What inventory approach contributes to process quality by "lowering the river to find the rocks?"
Lean (or JIT).
The amount of variation in the dependent variable that is explained by the variation in the independent variable(s).
The House of Quality.
Blame.

36. What happens to control limits on an SPC chart when sample size is increased?
A diagram that shows the relationships between activities in a project network.
They move closer to the center line.
Concluding there has not been an effect/change when there has.
X-bar-bar

37. Presence of interaction effect
A time series plot.
If the Response vs. Levels graph if the response lines are not parallel (crossing)
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 secondary characteristics of a product; "bells and whistles."

38. Defect location check sheets
95%
Used to create frequency distribution tally sheets
Actual drawings - layouts - maps - etc which show where a defect occurs
= y = Beta(0) + Beta(1)X + epsilon y=dependent variable (response) x=independent variable (predictor of y) - epsilon=error component - Beta(not)=intersection. If data include zero - it represents the mean of the distribution of y when - x=0. It does

39. In the Service Quality Gap Model - what is Gap 4?
A chart that breaks the range of data into equal intervals and then shows the count of occurrences in each interval.
The gap between what is promised and what is delivered.
It's good -- but it's still out of control!
Failure Modes and Effects Analysis

40. List two components of prevention cost.
95%
A random variable that summarizes the information from the sample(s).
Used to create frequency distribution tally sheets
Quality planning - design review - education and training - process control - IS costs - quality reporting - improvement project costs - working with suppliers before production.

41. With Six Sigma capability - how many defects per million opportunities would you see?
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
3.4 (assuming 1.5 sigma shift in the mean)
An interaction is defined as a dependence relationship between the response and the levels of two or more variables
To monitor a process when measurement by attribute is used.

42. What is poka yoke?
Fitness for use.
Mistake-proofing.
Critical to quality.
Stratify a particular defect type according to logical criteria

43. What is the role of a black belt?
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).
To manage the Six Sigma project.
Blame.
The US national quality award.

44. Define product reliability.
An experiment where one or more variables believed to have an effect on an experimental outcome are identified and manipulated according to a plan
Represent the errors which are random variables with an assumed normal distribution with mean zero and a constant variance σ2.
Mean time to failure.
Outside.

45. In a regression - what does the coefficient of the intercept tell you
The ratio of outputs to inputs; 1-scrap.
Lower control limit.
Sampling for SPC is done real time.
What the value of the dependent variable is when the independent variable is zero.

46. What is Jidoka?
5%
Critical to quality.
Controlling quality at the source.
10 if Almost impossible to detect

47. To what does the Six in Six Sigma relate?
The target number of standard deviations from the mean for specifications.
Rapid improvement process.
How much variance you expect around the prediction; two SEs gives you a 95% confidence interval.
Supplier - input - process - output - customer.

48. Define conformance quality.
Lower control limit.
Actual drawings - layouts - maps - etc which show where a defect occurs
The degree to which a product meets pre-established standards.
Large enough to find two of the attribute - on average.

49. If you have calculated a Cpk - should you also calculate a Cp?
= y = Beta(0) + Beta(1)X + epsilon y=dependent variable (response) x=independent variable (predictor of y) - epsilon=error component - Beta(not)=intersection. If data include zero - it represents the mean of the distribution of y when - x=0. It does
No; if the process is centered - Cp will be the same; if not - Cpk is what you need to determine capabilty.
To manage the Six Sigma project.
Pleasing to the senses.

50. Define perceived quality (Garvin's framework).
Initiated before or at design concept finalization
How much variance you expect around the prediction; two SEs gives you a 95% confidence interval.
Brand image.
Define - measure - analyze - design - verify.