bit 3414 quiz 2 WITH COMPLETE
SOLUTIONS GRADED A+ 2025/2026
Statistical process control (spc) - CORRECT ANSWER ✔✔monitors a production process to detect
and prevent poor quality
-does the process vary from what it is supposed to be doing?
-topic with SQC 1920s
-corrects the process before it starts producing defects
key tool is a control chart - CORRECT ANSWER ✔✔-periodically take a sample from a process
-calculate a statistic of interest from the sample
-plot the statistic on a control chart
-determine if the process is in control
-prevent quality problems
process control chart - CORRECT ANSWER ✔✔-does it change the way its supposed to?
signs of a process in control - CORRECT ANSWER ✔✔-no sample points outside limits
-most points near process average
-about equal number of points above and below center line
-points appear randomly distributed (no discernible pattern)
, if the process is in control, the sampling distribution of the plotted statistic should be ~normal
(and the empirical rule applies)
1 standard deviation - CORRECT ANSWER ✔✔68% falls within 1 sd
2 sd - CORRECT ANSWER ✔✔95% falls between 2 sd
3 sd - CORRECT ANSWER ✔✔99.74% falls between 3 sd
-always set the control limits 3o from the process average
types of variation observed - CORRECT ANSWER ✔✔-assess the chart to determine if the
variation present is inherent to the process or if it needs to be removed
common causes of variation - CORRECT ANSWER ✔✔-ever present factors that contribute to
small, random shifts in output
-difficult to track to a source
-inherent in the system/process
-present when in control
special causes of variation - CORRECT ANSWER ✔✔-identifiable factors that induce variation
beyond the inherent variation in the system
-can usually be tracked to a source
-process is NOT in control when present
initial construction of a control chart - CORRECT ANSWER ✔✔the first control chart built for a
process should be a benchmark when when the process is "in-control"
steps: - CORRECT ANSWER ✔✔1. decide what to measure or count (attribute vs. variable data)
SOLUTIONS GRADED A+ 2025/2026
Statistical process control (spc) - CORRECT ANSWER ✔✔monitors a production process to detect
and prevent poor quality
-does the process vary from what it is supposed to be doing?
-topic with SQC 1920s
-corrects the process before it starts producing defects
key tool is a control chart - CORRECT ANSWER ✔✔-periodically take a sample from a process
-calculate a statistic of interest from the sample
-plot the statistic on a control chart
-determine if the process is in control
-prevent quality problems
process control chart - CORRECT ANSWER ✔✔-does it change the way its supposed to?
signs of a process in control - CORRECT ANSWER ✔✔-no sample points outside limits
-most points near process average
-about equal number of points above and below center line
-points appear randomly distributed (no discernible pattern)
, if the process is in control, the sampling distribution of the plotted statistic should be ~normal
(and the empirical rule applies)
1 standard deviation - CORRECT ANSWER ✔✔68% falls within 1 sd
2 sd - CORRECT ANSWER ✔✔95% falls between 2 sd
3 sd - CORRECT ANSWER ✔✔99.74% falls between 3 sd
-always set the control limits 3o from the process average
types of variation observed - CORRECT ANSWER ✔✔-assess the chart to determine if the
variation present is inherent to the process or if it needs to be removed
common causes of variation - CORRECT ANSWER ✔✔-ever present factors that contribute to
small, random shifts in output
-difficult to track to a source
-inherent in the system/process
-present when in control
special causes of variation - CORRECT ANSWER ✔✔-identifiable factors that induce variation
beyond the inherent variation in the system
-can usually be tracked to a source
-process is NOT in control when present
initial construction of a control chart - CORRECT ANSWER ✔✔the first control chart built for a
process should be a benchmark when when the process is "in-control"
steps: - CORRECT ANSWER ✔✔1. decide what to measure or count (attribute vs. variable data)
