Page 443 - The Handbook for Quality Management a Complete Guide to Operational Excellence

430 A p p e n d i x D S i m u l a t e d C e r t i f i c a t i o n E x a m Q u e s t i o n s 431

76. Random selection of a sample:
a. theoretically means that each item in the lot had an equal chance to
be selected in the sample.
b. ensures that the sample average will equal the population average.
c. means that a table of random numbers was used to dictate the
selection.
d. is a meaningless theoretical requirement.

77. An X-bar and R chart was prepared for an operation using 20 samples
with five pieces in each sample. X was found to be 33.6 and R was
6.2. During production a sample of five was taken and the pieces
measured 36, 43, 37, 34, and 38. At the time this sample was taken:
a. both average and range were within control limits.
b. neither average nor range was within control limits.
c. only the average was outside control limits.
d. only the range was outside control limits.
e. The information given is not sufficient to construct an X-bar and R
chart using tables usually available.
78. A chart for number of defects is called:
a. np chart.
b. p chart.
c. X chart.
d. c chart.

79. A process is checked at random by inspection of samples of four shafts
after a polishing operation, and X and R charts are maintained. A
person making a spot check measures two shafts accurately, and plots
their range on the R chart. The point falls just outside the control limit.
He advises the department foreman to stop the process. This decision
indicates that:
a. the process level is out of control.
b. the process level is out of control but not the dispersion.
c. the person is misusing the chart.
d. the process dispersion is out of control.

80. A process is in control with p = 0.10 and n = 100. The three-sigma limits
of the np-control chart are:
a. 1 and 19.
b. 9.1 and 10.9.
c. 0.01 and 0.19.
d. 0.07 and 0.13.
81. A p char:
a. can be used for only one type of defect per chart.
b. plots the number of defects in a sample.

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