Page 440 - Six Sigma Demystified

420 Six SigMa DemystifieD

34. Process flowcharts can be used to
A. uncover differences in stakeholders’ perceptions of the process.
b. communicate process changes.
c. discover process complexities that contribute to variation or longer cycle times.
d. All the above are true.

35. The prime use of a control chart is to
A. detect assignable causes of variation in a process.
b. detect nonconforming product.
c. measure the performance of all quality characteristics of a process.
d. detect the presence of random variation in a process.

36. Which of the following is the correct control chart for the waiting time for
customers in a bank (each individual customer’s waiting time will be plotted)?
A. U chart
b. Individual-X/moving range
–
c. X and s
d. Np chart

37. When are control charts for individuals’ data necessary?
A. The rational subgroup size is 1.
b. There is only one characteristic to be monitored.
c. It is always the best choice for control charting.
d. All the above are true.

38. A disadvantage of control charts for individuals’ data is
A. that there are fewer data to collect.
b. that they are less sensitive to process shifts than larger subgroups.
c. that they work only for autocorrelated processes.
d. All the above are true.

39. An advantage of using control charts for individuals’ data is
A. that there are fewer data to collect.
b. that the control limits can be compared directly with the specifications.
c. that they cost less than larger subgroup sizes.
d. All the above are true.

40. When an observation is beyond the 3s limits on an individual-X chart,
A. you should wait to see if more observations go beyond the limits because there is
a chance that subgroups will be out of control when the process has not shifted.
b. you should respond immediately because the chance of an out-of-control point is
very small unless the process has shifted.
c. you should see if the point also fails run-test rules before responding.
d. you should respond only if the characteristic is critical to the customer.