Chapter 12 Quality Control 519
is out of control? What factors, if any
might have contributed to this?
c. Save your changes to the workbook
and write a report of your observa-
tions and conclusions.
- The number of fl aws on the surfaces of
a particular model of automobile leav-
ing the plant was recorded in the Autos
workbook for each of 40 automobiles
during a one-week period.
a. Open the Autos workbook from the
Chapter2 folder and save it as Autos
Control Chart.
b. Create a control chart of the count of
auto fl aws. Is this process in control?
c. Save your changes to the workbook
and report your results.
- You’ve learned in this chapter that fi ller
head 18 is a major factor in the number
of defective fi lls. To investigate further,
you decide to look at the head 18 values
from the data set to determine at what
points in time the head was out of statis-
tical control.
a. Open the Powder workbook from the
Chapter12 folder and save it as Powder
Control Chart.
b. Create an Individuals chart and a
moving range chart of the Head 18
values. At what times are the head
values beyond the control limits?
c. Repeat part b for fi ller heads 14 and 23.
d. Interpret your fi ndings in light of the
fact that a new shift comes in at mid-
night. Does this fact affect the fi ller
process?
e. Save your changes to the workbook
and write a report summarizing your
observations.
- Weather can be considered a process
with process variables such as tem-
perature and precipitation and attribute
variables such as the number of
hurricanes and tornadoes in a given
season. One theory of meteorology
holds that climatic changes in this
process take place over long periods
of time, whereas over short periods of
time, the process should be stable. On
the other hand, concerns have been
raised about the effect of CO 2 emis-
sions on the atmosphere, which may
lead to major changes in the weather.
You’ve been given the yearly tem-
perature values for northern Illinois
from 1895 to 1998, saved in an Excel
workbook.
a. Open the Temp100 workbook from
the Chapter12 folder and save it as
Temp100 Control Chart.
b. Create an Individuals chart and a
moving range chart of the average
yearly temperature.
c. What is the average yearly tempera-
ture? What are the lower and upper
control limits? Do the temperature
values appear to be in statistical
control?
d. Create a moving range chart of the
average yearly temperature. Does this
chart show any violations of process
control?
e. Save your changes to the workbook
and write a report summarizing your
results.
- The Rain100 workbook contains the
total precipitation for northern Illinois
from 1895 to 1998.
a. Open the Rain100 workbook from
the Chapter12 folder and save it as
Rain100 Control Chart.
b. Create an individuals chart of the
total precipitation.
c. Create a moving range chart of the
total precipitation.
d. Does the process appear to be in sta-
tistical control? Save your workbook
and report your conclusions.
