COB 300 Operations Exam #2 Questions
and Answers
quality control - Answers -process that evaluates output relative to a standard and takes
corrective action when output doesn't meet standards
acceptance sampling - Answers -approach to quality assurance where inspection is
done before/after production; least progressive approach
process control - Answers -approach to quality assurance where inspection and
corrective action is done during production
continuous improvement - Answers -approach to quality assurance where quality is built
into the process; most progressive approach
inspection - Answers -appraisal of goods or services; used to provide information on the
degree to which items conform to a standard
low-cost, high-volume items (paper clips, roofing nails, wooden pencils) require: -
Answers -little inspection because the cost associated with passing defective items is
quite low and the processes that produce these items are highly reliable so defects are
rare
high-cost, low-volume items require: - Answers -more intensive inspection; automated
inspection is an option that can be used
quality conformance - Answers -product or service conforms to specifications
statistical process control (SPC) - Answers -statistical evaluation of the output of a
process; used to decide if a process is in control or if corrective action is needed
random variation - Answers -natural variation in the output of a process, created by
countless minor factors; common variability (variations are so minor that it is
unimportant to attempt to eliminate them)
assignable variation - Answers -in process output, a variation whose cause can be
identified; non-random variation
sampling distribution - Answers -theoretical distribution of sample statistics; most
frequently used is normal distribution
, central limit theorem - Answers -distribution of sample averages tends to be normal
regardless of the shape of the process distribution
How is control achieved? - Answers -by checking a portion of the goods or services,
comparing the results to a predetermined standard, evaluating departures from the
standard, taking corrective action when necessary, and following up to ensure that
problems have been corrected
control chart - Answers -time-ordered plot of sample statistics, used to distinguish
between random and nonrandom variability; has upper and lower limits to define range
of acceptable variation from the sample statistic
control limits - Answers -dividing lines between random and nonrandom deviations from
the mean of the distribution
Type I error - Answers -concluding a process is not in control when it actually is; also
referred to as alpha risk
Type II error - Answers -concluding a process is in control when it is not
variables - Answers -generate data that are measured (amount of time needed to
complete a task, length or width of a part)
attributes - Answers -generate data that are counted (ex number of defective parts in a
sample, the number of calls per day)
mean control chart/x-bar chart - Answers -control chart used to monitor the central
tendency of a process
upper control limit (UCL) for x-bar chart - Answers -x-bar-bar + z(standard deviation of
x-bar)
lower control limit (LCL) for x-bar chart - Answers -x-bar-bar - z(standard deviation of x-
bar)
standard deviation of x-bar - Answers -process standard deviation/square root(sample
size)
range control chart - Answers -control chart used to monitor process dispersion
upper control limit (UCL) for R-chart - Answers -D4(R-bar)
lower control limit (LCL) for R-chart - Answers -D3(R-bar)
p-chart - Answers -control chart for attributes, used to monitor the proportion of
defective items in a process
and Answers
quality control - Answers -process that evaluates output relative to a standard and takes
corrective action when output doesn't meet standards
acceptance sampling - Answers -approach to quality assurance where inspection is
done before/after production; least progressive approach
process control - Answers -approach to quality assurance where inspection and
corrective action is done during production
continuous improvement - Answers -approach to quality assurance where quality is built
into the process; most progressive approach
inspection - Answers -appraisal of goods or services; used to provide information on the
degree to which items conform to a standard
low-cost, high-volume items (paper clips, roofing nails, wooden pencils) require: -
Answers -little inspection because the cost associated with passing defective items is
quite low and the processes that produce these items are highly reliable so defects are
rare
high-cost, low-volume items require: - Answers -more intensive inspection; automated
inspection is an option that can be used
quality conformance - Answers -product or service conforms to specifications
statistical process control (SPC) - Answers -statistical evaluation of the output of a
process; used to decide if a process is in control or if corrective action is needed
random variation - Answers -natural variation in the output of a process, created by
countless minor factors; common variability (variations are so minor that it is
unimportant to attempt to eliminate them)
assignable variation - Answers -in process output, a variation whose cause can be
identified; non-random variation
sampling distribution - Answers -theoretical distribution of sample statistics; most
frequently used is normal distribution
, central limit theorem - Answers -distribution of sample averages tends to be normal
regardless of the shape of the process distribution
How is control achieved? - Answers -by checking a portion of the goods or services,
comparing the results to a predetermined standard, evaluating departures from the
standard, taking corrective action when necessary, and following up to ensure that
problems have been corrected
control chart - Answers -time-ordered plot of sample statistics, used to distinguish
between random and nonrandom variability; has upper and lower limits to define range
of acceptable variation from the sample statistic
control limits - Answers -dividing lines between random and nonrandom deviations from
the mean of the distribution
Type I error - Answers -concluding a process is not in control when it actually is; also
referred to as alpha risk
Type II error - Answers -concluding a process is in control when it is not
variables - Answers -generate data that are measured (amount of time needed to
complete a task, length or width of a part)
attributes - Answers -generate data that are counted (ex number of defective parts in a
sample, the number of calls per day)
mean control chart/x-bar chart - Answers -control chart used to monitor the central
tendency of a process
upper control limit (UCL) for x-bar chart - Answers -x-bar-bar + z(standard deviation of
x-bar)
lower control limit (LCL) for x-bar chart - Answers -x-bar-bar - z(standard deviation of x-
bar)
standard deviation of x-bar - Answers -process standard deviation/square root(sample
size)
range control chart - Answers -control chart used to monitor process dispersion
upper control limit (UCL) for R-chart - Answers -D4(R-bar)
lower control limit (LCL) for R-chart - Answers -D3(R-bar)
p-chart - Answers -control chart for attributes, used to monitor the proportion of
defective items in a process
