Reading and Comprehension Questions for Chapter 16
1. Quality improvement is synonymous with elimination of waste.
True False
True
2. Statistical process control consists of the following problem-solving tools:
a. Histogram
b. Pareto chart
c. Cause-and-effect diagram
d. Defect concentration diagram
e. Control chart
f. Scatter diagram
g. Check sheet
h. All of the above
Answer is h
3. Chance and assignable causes of variation are both inherent parts of the process.
True False
False
4. A process that is operating without any assignable causes present is said to be in-control.
True False
True
5. If all points plot inside the limits on a control chart, it is always safe to conclude that the process is in statistical control.
True False
False
6. The usual distance of the control limits from the center line on a Shewhart control chart is three times the standard deviation of the statistic plotted on the chart.
True False
True
7. Variables control charts are used for defect data.
True False
False
8. Current industry practice when using control charts is to take large but relatively infrequent samples.
True False
False
9. Taking sample observations close together in time is a frequent basis for rational subgrouping of data for a control chart.
True False
True
10. Which of the following is not one of the Western Electric rules for control chart interpretation?
a. One point plots outside 3-sigma control limits
b. Two out of three consecutive points plot beyond a two-sigma limit
c. Four out of five consecutive points plot at a distance of 1-sigma or beyond from the center line
d. Ten consecutive points plot on one side of the center line
Answer is d
11. The chart is used to monitor the process average and either an R or an S chart can be used to monitor process variability.
True False
True
12. Typical sample sizes used on the chart are
a. 4
b. 5
c. 6
d. All of the above
e. None of the above.
Answer – d.
13. Control charts for individual measurements are often used in conjunction with automated test and measurement technology.
True False
True
14. On an individuals control chart, we usually use a pooled estimate of the standard deviation to construct the control limits.
True False
False
15. Specification limits are useful in helping determine where to set the limits on a control chart.
True False
False
16. The process capability ratio PCRk provides a measure of potential capability in the process.
True False
False
17. The Uchart is used to monitor proportions.
True False
False
18. Average run length is a standard way to express control chart performance.
True False
True
19. The in-control average run length of an chart with 3-sigma control limits is
a. 500
b. 450
c. 370
d. None of the above
Answer is c
20. The cumulative sum chart can detect small shifts in the process mean more quickly that the chart.
True False
True
21. The average run length (ARL) to detect changes in the process mean for an EWMA control chart is roughly comparable to the ARL for a CUSUM.
True False
True
22. Deming’s 14 points for management were primarily about the use of control charts.
True False
False