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Green Belt Questions1. What is a designed experiment? Answer in 25 words or less

2. Which of the following is not a benefit of a designed experiment?(a) Identifies main and interaction effects(b) Analyses different combinations of inputs(c) Relatively low cost to implement(d) Can be easily used to make improvements to random processes

3. Which of these defects per million opportunity (DPMO) levels approximates tofour Sigma quality?(a) 308,357(b) 66,807(c) 6,210(d) 233(e) 3.4

4. What is the difference between common cause and special cause variation?

5. What is a Gage R& R analysis?

6. In an effective measurement system, is repeatability or reproducibility likely to be a more significant source of variation?

7. Calculate the temperature main effect in this 2k factorial experiment.Temp........Mat.......Yield- 1 ............-1..........621............-1...........74

-1..............1...........561.............. 1.......... 70

8. According to Eli Goldratts Theory of Constraints, which is the optimal strategy?(a) Identify the constraint, decide how to exploit it, subordinate production upto the level of the bottleneck, then seek to elevate the constraint.(b) Stockpile inventory ahead of the bottleneck for maximum control of throughput.(c) Constraints should never be elevated.

(d) Work simultaneously on eliminating all constraints.

9. Which of these is the best definition of takt time?(a) Pace of a manufacturing system as determined by customer demand(b) Average time taken to complete a task under normal operating conditions(c) The maximum operating speed of a process or production line(d) The long-run historic performance capacity of a system.

10. Which of these can form part of the visual factory?(a) Yamazumi Boards(b) Process Maps(c) Kanban Signals(d) All of the above

Green Belt Answers1. A designed experiment involves varying input factors (Xs) to find out which variables, or combination of variables, deliver optimised output (Y).2. Answer (d). It is hard to make improvements to a random process where the Green Belt has no ability to influence factor input levels.3. 6,210 defects per million opportunities represent four sigma quality. Six Sigma quality levels approximate to 3.4 defects for every million repetitions of aprocess world class quality.4. All processes exhibit variation due to machines, materials, methods, measurement systems, people and nature. Common cause variation is long-term, random and

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predictable within the normal distribution of the process. Special cause variation is unusual, unpredictable and typically arises from excessive influence of one source of variation.5. A Gage R&R analysis is a process to determine measurement system error. Thishas two components repeatability (inherent variability of the measurement system measured by the same operator under identical conditions) and reproducibility (variability between operators when measuring the same item).6. Typically human error is greater than machine error, so reproducibility is the larger component of measurement system variation.7. Temp Effect = Average of 1 Yields less Average of -1 YieldsTemp Effect = (74+70)/2 less (62+56)/2 = 72 59 = 138. Goldratt suggested a five step process which involved identifying the constraint, working out how to get maximum output from the constrained process, subordinating the production level up to the bottleneck (to avoid a surplus of inventory building up) and then finally working to elevate (or eliminate) the constraint.9. (a) is the best answer. Takt time sets the pace for manufacturing lines. In automobile manufacturing, for example, cars are assembled on a line, and are moved on to the next station after a certain time - the takt time. Takt time aims tomatch the pace of production with customer's demand.10. All of the above - since these are all visual techniques