Statistical Quality Control Multiple Choice Questions on “Gauge and Measurement System Capability Studies – 1”.
1. Which of these is not an objective of most measurement systems capability studies?
a) Determining how much of variability is due to the gauge or instrument
b) Isolating the components of variability in measurement system
c) Assessing whether the instrument is capable
d) Checking whether the instrument can make defective pieces
Clarification: Most measurement system capability studies are having objectives like determination of the amount of variability due to the gauge or instrument, to isolate the components of variability in the measurement system etc.
2. Which of these is one of the two R’s of measurement systems capability?
Clarification: The two R’s of the measurement systems capability are “Reproducibility” and “Repeatability”. They play very important role in the measurement system capability studies.
3. What is repeatability of a measurement instrument?
a) Getting the maximum value of the measured dimension
b) Getting the minimum value of the measured dimension
c) Getting the exact value of the measured dimension
d) Same observation value for same measured dimension for several times
Clarification: Repeatability of a measurement instrument is defined as getting the same observed value if we measure the same unit several times under identical conditions.
4. What is reproducibility of a measurement system?
a) Difference between the observed values when the measuring conditions are same
b) Difference between the observed values when the measuring conditions are different
c) Ease in measurement when the measuring conditions are same
d) Ease in measurement when the measuring conditions are different
Clarification: Reproducibility is how much difference we get in observed values, when the units are measured under different conditions like different operators, time periods etc.
5. Measurement system capability ____________ when the good unit is judged to be defective.
c) Does not change
d) Can’t be evaluated
Clarification: The capability of a measurement system decreases substantially when the good unit in the output of a process is judged to be defective. This is a fault of the measurement system.
6. Measurement system capability increases if the bad unit is judged to be _____________
c) Not defective
d) Satisfying the specifications
Clarification: When a measurement system identifies a bad unit by classifying it as nonconforming, the measurement system capability is increased.
7. If a good unit is judged to be conforming, what will be the effect on the measurement system capability?
c) Remain same
d) Can’t be calculated in this case
Clarification: If a good unit is judged to be conforming to the standards and specifications, it indicates the efficiency of the system. So the capability of the measurement system is increased in this case.
8. What is the linearity of a measurement system?
a) Differences in observed accuracies and/or precision over a range of measurements made
b) Differences in theoretical accuracies and/or precision over a range of measurements made
c) Differences in products dimensions of products from a same process
d) Differences in the product quality from a same process
Clarification: Linearity of a measurement system is defined as the differences in observed accuracy and/or precision, experienced over the range of the measurements made by the system.
9. When the measurement system is not linear ____________ is needed.
a) Process to be changed by which the units are made
b) Calibration of the measurement system
c) Change in the process parameters
d) No change
Clarification: If there are problems with linearity of the measurement system, they can be due to calibration or maintenance issues, so proper calibration or the replacement of the measurement system can solve the problems.
10. Which of these is not a cause of the stability defects in the measurement systems?
a) Warm up effects
b) Environmental factors
c) Inconsistent operator performance
d) Maintenance errors
Clarification: Stability or different levels of variability in different operating regimes, can result from warm-up effects, environmental factors, inconsistent operator performance, and inadequate standard operating procedures.
11. Bias of a measurement instrument is defined as ___________
a) The difference between the observed value and the true value
b) The difference between the observed value and the lowest possible value
c) The difference between the observed value and the estimated value
d) The difference between the observed value and the highest possible value
Clarification: The bias of a measurement system reflects the difference between the observed value and the true value obtained from a master or gold standard, or from a different measurement technique reliable to produce accurate values.
12. It becomes very difficult to monitor, control, improve, or effectively manage a process with _____________ measurement system.
a) A passable
b) A satisfactory
c) An adequate
d) An inadequate
Clarification: If the measurement system is not capable to produce good results, it becomes very difficult to monitor, control, improve, or effectively manage a process with an inadequate measurement system.
13. MSA stands for ________________
a) Million standards analysis
b) Major system analysis
c) Measurement system analysis
d) Master system analysis
Clarification: MSA is an acronym used for Measurement System Analysis, which is done in the measurement system capability analysis.
14. An ineffective measurement system can dramatically impact business performance.
Clarification: It is true that an ineffective measurement system can dramatically impact business performance because it leads to uninformed and usually bad decision making.
15. Measurement system can also cause variability in the products.
Clarification: Generally, in an activity that involves measurements, some of the observed variability will be inherent in the units or items that are being measured, and some of the variability will result from the measurement system used.