SQC
HW#4
Eric Klopp
3/9/05
14. What information is provided by the operating characteristic curve of a control
chart?
The operating characteristic curve provides information such as the process mean and
the probability of that mean falling between the control limits.
18. Consider the control chart shown here. Does the pattern appear random?
The pattern does, in fact, appear to be random.
22. Sketch warning limits on the control chart in exercise 4-19. Do these limits
indicate any potential out-of-control conditions?
There does appear to be several points that
exceed the warning limit. This could quite
possibly indicate an out-of-control condition.
23. Apply the Western Electric rules to the control chart presented in exercise 4-19.
Would these rules result in any out-of-control signals?
Two of the rules apply to this exercise: Two
out of three consecutive points plot outside
the two-sigma warning limit, and Four out
of five consecutive points plot at a distance
of one-sigma or beyond from the center line.
These would definitely result in out-ofcontrol signals.
24. Consider the time-varying process behavior shown in Figs. a-e. Match each of
these several patterns of process performance to the corresponding x and R charts
shown in Figs. 1-5.
a)  #2
b)  #4
c)  #5
d)  #1
e) #3
SQC
HW#4
Eric Klopp
3/9/05
26. A car has gone out of control during a snowstorm and struck a tree. Construct a
cause-and-effect diagram that identifies and outlines the possible causes of the
accident.
Driver error
Reckless
driving
Passenger error
Distracting
driver
Fatigue/
Inattentiveness
Struck a tree
Mechanical
Failure
Car failure
wind
and ice
Slippery
roadway
Fierce act
of God
Outside forces
29. Develop a flow chart for the process that you follow every morning from the
time you awake until you arrive at your school. Identify the value-added and
nonvalue-added activities.
to
living
room
Value added
Non-value added
Shut
off
alarm
put on
coat and
back pack
walk to
school
do business
take shower
wake
up
to bathroom
to
get dressed living
room
to shower
put on
walk to
coat and school
back pack
to
bedroom get
dressed
check
email
to
make
eat
kitchen breakfast
put on
walk to
coat and school
back pack
SQC
HW#4
Eric Klopp
3/9/05
31. Develop a check sheet to record “defects” you have in your personal life. Use the
check sheet to keep a record of these “defects” for one month. Use a Pareto chart to
analyze these data. What are the underlying causes of these “defects”?
Defect
Overeating
Not doing
homework
Skipping class
Watching too
much tv
Snacking
between meals
Picking on
roommates
Leaving dishes
on counter top
Forgetting to
take out trash
Monthly Data Check Sheet
Week 1
Week 2
Week 3
|||
|
|||||
|
||
Week 4
||
||||
|
|||
||||||
||||
|||
||
||||
||
|||
|||||||
|||
|
||
|
||||
||
|
|
|
Pareto Chart for Monthly Data
18
16
14
12
10
8
6
4
2
wa
tc
hi
ng
to
pi
o
ck
m
in
uc
g
h
o
n
sn
tv
ro
ac
om
kin
m
g
at
be
es
tw
ee
n
le
m
av
ea
in
ls
g
o
di
ve
sh
re
es
at
fo
on
in
rg
g
et
co
t in
un
g
te
to
rt
ta
op
ke
ou
no
tt
td
ra
oi
sh
ng
ho
m
ew
or
sk
k
ip
pi
ng
cl
as
s
0
There are several underlying causes of these “defects”, but I think the main ones are
stress and laziness. The stress of getting school work done and performing well may
cause the poor eating habits, which are considerable “defects.” The laziness factor causes
results like watching too much tv and leaving the dirty dishes on the kitchen counter top.
This type of analysis can be beneficial to observe defects that may go unnoticed as well
as make it easier to think of solutions to prevent these defects from occurring.