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CHAPTER 21 SECTION 4: STATISTICAL PROCESS CONTROL
MULTIPLE CHOICE
105.
Control charts that are used to monitor a process whose results are categorized as either defective or
nondefective are called:
a.
p
chart
b.
S
chart
c.
x
chart
d.
None of these choices.
ANS: A
PTS: 1
REF: SECTION 21.4
106.
If the lower control limit for the
p
chart is negative, we set it equal to
107.
Forty samples of size 800 were drawn from a manufacturing process and the number of defectives in
each sample was counted. The mean sample proportion was 0.035. The lower control limit for the
p
chart is:
108.
Twenty samples of size 1,500 were drawn from a manufacturing process and the number of defectives
in each sample was counted. The mean sample proportion was 0.020. The upper control limit for the
p
chart is:
TRUE/FALSE
109.
Forty samples of size 2,500 were taken from a production process that is under control. The mean of the
sample proportions of defectives was 0.05. The lower control limit for the 3sigma
p
chart is 0.0369.
ANS: T
PTS: 1
REF: SECTION 21.4
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110.
Control limits for the
p
chart are typically placed so that they are 3 standard errors above and below the
centerline.
ANS: T
PTS: 1
REF: SECTION 21.4
111.
When the purpose of sampling is to detect when a process becomes too variable, the chart of choice will
be a
p
chart.
ANS: F
PTS: 1
REF: SECTION 21.4
112. The
p
chart is an example of control charts for attributes.
ANS: T
PTS: 1
REF: SECTION 21.4
113.
Fifty samples of size 1,000 were drawn from a manufacturing process and the number of defectives in
each sample was counted. The mean sample proportion was 0.05. The centerline for the
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 Spring '10
 Kumar
 Control Chart, REF, LCL, Lower control limit

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