X-Man Problems
Dr. Everette S. Gardner, Jr.
Terry Collins, CEO, Wildflour Pizza
Terry Collins, CEO of Wildflour Pizza in Missouri City, Texas, collects data concerning
customer complaints about delivery. Here are the results for the last 30 days:
Problem
Topping stuck to box lid
Pizza is late
Wrong topping/combination
Wrong style of crust
Wrong size
Pizza is partially eaten
Pizza never showed up
Total
Frequency
17
35
9
6
4
3
6
80
Assignment
1. Use a Pareto chart to help Terry identify the vital delivery problems.
2. Draw a fishbone chart to help Terry identify potential causes of late pizza delivery.
X-Man
2
Country Star Nissan, Rosenberg, Texas
David Lee Murphy, General Manager of the Country Star Nissan dealership in
Rosenberg, Texas, liked to get to the office early so that he could practice guitar riffs
before the business day started. He had just cranked up “Dust on the Bottle” when
his secretary, Patty Loveless, barged in. Patty looked flustered and said, “David Lee,
you better put down that fool guitar and look at this letter.” The contents are
reproduced below:
Dear Mr. Murphy:
I am writing this letter to make you aware of a nightmare I experienced in getting my
300ZX repaired in your body shop and service department. Here is a chronology of
events:
August 28
Dropped off the car for repair of rust damage on roof along windshield area, left
rocker panel under driver’s door, and left quarter panel near end of bumper.
September 1
Called to inquire about the status of the car (this was the fifth day in the shop). Was
told I could pick up the car anytime after 2 pm. My boyfriend and I arrived at 5 pm but
the car was not ready. I paid the bill of $443.17 and waited. At 6 pm, the car was
driven up dripping wet. (I assume the car was washed but can’t you dry it off before
you return it?) I got in and noticed the courtesy light in the driver’s door would not go
off when the door was closed. I asked for help and Pam Tillis, body shop manager,
could not figure out what was wrong. She removed the bulb and told me to come
back after Labor Day. I started the engine and drove off but the voice warning “Left
door is open” repeatedly sounded. There was no way to turn it off. I returned to Ms.
Tillis and told her to keep the car until it was fixed. Ms. Tillis told me to call the next
day (Saturday).
September 2
I called Ms. Tillis at 10:30 am. She said that the car had not been looked at yet. She
promised to call back before the shop closed for the holiday but she never did.
September 5
I called Ms. Tillis at 4 pm. Nothing had been done but the car would be ready the
next day.
X-Man
3
Country Star Nissan, Rosenberg, Texas
September 6
I called Ms. Tillis at 3 pm. She said that the service department needed authorization
to fix the car and they didn’t know how much it would cost. I became very upset at
the hint that I would have to pay to fix the door light and voice warning. I demanded
to see the service manager, Shania Twain. She assured me that I was not financially
responsible for any problems caused by the body shop. Furthermore, my car would
be ready the next day.
September 7
Again late in the day, I called Ms. Twain. She said her best mechanic, Lorrie Morgan,
had narrowed down the problem to a wire that passed several spots where body work
was done. She referred the call to Ms. Morgan, who assured me that the car would
be ready tomorrow.
September 8
I called Ms. Twain to check on the status. She told me that the wiring was fixed but
the speedometer didn’t work. Lorrie Morgan got on the line and said that when she
test-drove the car, the speedometer pinned itself at the top end. She thought that
one of the other mechanics must have done something to the speedometer while
searching for the other problem. She told me that I could pick up the car but I would
have to return in next Monday so that a subcontractor could fix the speedometer. Ms.
Twain said that Ft. Bend Nissan would pay all charges.
I arrived at 5 pm. As I walked up to the car, I noticed rubber molding hanging down
below the driver’s door. I asked Ms. Twain to come and look at it. She said that it
must have come loose while they were repairing the wiring problem. She took the
car back into the shop to screw the molding back in. When she finished, the molding
looked sloppy. I complained about this and Ms. Twain said they would replace the
molding next Monday. Driving home, I discovered that the anti-theft light on the dash
would not stop blinking. I had to remove the fuse to stop the blinking light but this deactivated the security system.
September 11
On Sunday evening, I dropped the car off and left a note with my keys in the “earlybird” slot. The note listed the following problems: molding, speedometer, and security
system. I explained that all of these things were o.k. when I originally brought the car
in for body work. On Monday, I got a call from Tanya Tucker in the service
department who said that it would cost $110 to repair the security system. The
problems were in the hatchback lock and in the wiring of the system. I asked her why
I had to pay for problems caused by Country Star Nissan.
X-Man
4
Country Star Nissan, Rosenberg, Texas
Ms. Tucker said that she had checked with the mechanics who worked on my car—
there was no way they caused the problems with the security system. I told Ms.
Tucker to forget the security system for now because I would take the problem up with
the general manager. I asked Ms. Tucker to get the molding and speedometer fixed
and get the car ready as soon as possible.
September 13
Ms. Tucker called and said I could pick the car up at 8 pm. I arrived at that time and
was presented a bill for $126 for speedometer repair and “miscellaneous labor” in
searching for the security system problem. I refused to pay the bill. I was told to take
the car home—the service manager would resolve the problem the next day. I asked
about the molding and was informed that it was not in stock and must be ordered.
Note that the molding was damaged on September 8.
As I got into the car, I noticed that the rear-view mirror was broken off its mounting
and was lying in the passenger seat. I asked to see Ms. Twain and demanded to
know how something like this could happen without anyone noticing. Ms. Twain was
not in but I talked to Mary Chapin-Carpenter, who said someone probably did not want
to own up to it. Ms. Chapin-Carpenter went to the parts department and got a new
mirror and installed it.
I realize this is a long letter, but I am extremely frustrated and upset by the mistakes
made by your dealership over the last three weeks. What are you going to do about
it?
Sincerely,
Leann Rimes
Assignment
1. Categorize the quality problems in this case.
2. Prepare a fishbone chart for “failure to resolve repair problem to customer’s
satisfaction.”
X-Man
5
The X-Man and Mammy Faye Baker
The X-Man is an ace relief pitcher and forkball specialist. During off-season periods,
X has developed a considerable international reputation as an expert in quality
assurance, management, and control. Currently he serves as a senior quality analyst
at Mammy Lash, Inc., a company located in Palestine, Texas, and founded by
Mammy Faye Baker. Mammy Lash manufactures eye shadow, false eyelashes, and
a variety of other eye-related beauty products.
Mammy Faye is concerned about the length of the horse hairs used in making
eyelashes. Horse hairs were selected as a raw material because they are quite
durable, although precision trimming is difficult. Therefore, X decided to sample the
trimming process. He took 4 samples of size 3 each with the following results:
Sample
1
2
3
4
Measurements
21
23
22
20
23
17
21
21
21
21
20
19
To simplify calculations, the measurements are stated as the number of millimeters
above 150. That is, the first measurement is actually 171 millimeters (6.73 inches),
the second is 173 millimeters (6.81 inches), and so on.
Help the X-Man answer the following questions:
1. Is the trimming process in control?
2. Mammy Faye decides that specifications for eyelash hair length be established.
The upper specification limit is 175 millimeters, with a lower specification limit of
165. Is the trimming process capable?
X-Man
6
The X-Man and the Vampire
The alert student will recall that the X-Man took an off-season job as quality analyst at
Mammy Lash, Inc., a manufacturer of eye-related beauty products. X is faced with
another serious quality problem, this time involving Mammy Lash’s “Vampire Bat” eye
shadow, which most consumers purchase in the personal size (by the barrel). Each
barrel should contain approximately 55 pounds of eye shadow. Mammy Faye Baker
is concerned about variation in actual weights of barrel contents.
X weighed 5 samples, each containing 4 barrels. He found that the mean of the
sample means was 54.4 pounds, while the mean of the sample ranges was 3.2
pounds.
Help the X-Man answer Mammy Faye’s questions:
1. What are the 3-standard-deviation control limits for the sample means and
ranges?
2. What percentage of sample means should fall inside the 3-standard-deviation
control limits, if the process is actually in control? What percentage should fall
outside the limits?
3. What is the range of expected natural or common-cause variation for individual
observations?
4. What percentage of individual observations should fall inside the range of natural
or common-cause variation? What percentage should fall outside the limits?
5. Mammy Faye would like to have 2-standard-deviation limits for means and ranges
to provide tighter control. What are the revised control limits for means and
ranges of samples of size 4?
X-Man
7
The X-Man and Roberto Alomar
The X-Man became increasingly unhappy in his off-season job at Mammy Lash, Inc.
The last straw was a memo from Mammy Faye Baker stating that all employees must
report to work each day wearing a complete collection of Mammy Lash products.
X moved back to Missouri City, Texas, where he took a job as Senior Vice President for
Quality Assurance and Control at Wildflour Pizza. The alert student will recall that
Wildflour customers sometimes complain that pizzas are delivered in a partially-eaten
condition. Wildflour’s CEO, Terry Collins, asked X to analyze this problem.
X collected data for deliveries during the first 5 days of November:
Sample #
1
2
3
4
5
Driver
Roberto Alomar
Orlando Miller
Roberto Alomar
Orlando Miller
Roberto Alomar
# delivered
1,000
300
1,500
1,000
100
# complaints that
pizza is partially eaten
4
1
14
0
3
Help the X-Man answer the following questions:
1. What type of control chart should be used to monitor these complaints?
2. Compute upper and lower control limits for the chart that you selected in question 1.
3. Is the process in control? Why or why not?
4. What assumptions about the data are necessary to use your chart?
X-Man
8
The X-Man and the Alligator
The alert student will recall that the X-Man took a position as Senior Vice President for
Quality Assurance and Control at Wildflour Pizza, Missouri City, Texas. X’s first
project at Wildflour was an investigation of customer complaints about partially-eaten
pizzas. X solved that problem by suspending the culprit, Roberto Alomar, for five
days. Although Roberto’s union, the Pizza Teamsters, requested that the suspension
be served during the off-season next year, X did not give in and Roberto served his
sentence.
Another quality problem has cropped up at Wildflour. The CEO, Larry Dierker (who
replaced Terry Collins at both Wildflour and the Astros), built a Cajun Sushi Bar at
Wildflour’s main restaurant location on Murphy Road, near Highway 6. The Bar
proved to be wildly popular, primarily due to its Alligator Sushi, composed of paperthin slices of fresh alligator marinated in corn liquor.
To ensure freshness of the product, Wildflour receives one live alligator each day from
its supplier in Hope, Arkansas. Alligator processing is a spectator sport at Wildflour.
When each alligator arrives, it is thrown into a pit in the center of the restaurant.
Accompanied by applause and cheers from customers, the executive chef, Danny
Darwin, dives into the pit and wrestles the alligator into submission. At this point,
Danny takes a much-needed shower while his assistant, John Cangelosi, takes over.
John slays the beast, dresses it, and slices it. The last step in processing is a good
dousing in corn liquor.
Danny is concerned about the consistency of the dressed weights of alligators. He
would like to receive alligators with dressed weights in a reasonable range of variation
around 500 pounds, the Bar’s average daily demand. Weights much above 500
pounds result in wasted sushi, which cannot be retained overnight or it will lose its
flavor. Weights much less than 500 pounds result in hungry customers that cannot be
served.
X-Man
9
The X-Man and the Alligator (cont.)
Danny asked X to set up a control chart to monitor the daily dressed weights of
alligators. Here are the weights collected by X for five consecutive days:
Day
1
2
3
4
5
Dressed weight (lbs.)
495
517
488
505
541
Help the X-Man answer the following questions:
1. What type of control chart is appropriate for this data?
2. What are the upper and lower control limits?
3. Is the process in control? Why or why not?
X-Man
10
The X-Man and Marvin Zindler
Marvin Zindler paid a surprise visit to Wildflour’s Cajun Sushi Bar. Although Marvin
liked the Gator Sushi, he was quite upset when he found slime in the ice machine.
During his Channel 13 broadcast, Marvin became so agitated that his wig flew off.
Wildflour’s owner, Drayton McClain, saw Marvin’s broadcast. He called the X-Man
into his office, read him the riot act, and ordered him to design a quality inspection
program for the company’s nationwide chain of 5,675 restaurant units. Drayton also
demanded a control chart to monitor inspection results.
X decided to randomly select restaurant units for surprise inspections. Any quality
problem in sanitation, restaurant design, equipment, food preparation, training,
delivery, or customer service would be counted as a defect. Thus there were an
extremely large number of opportunities for defects in any restaurant unit.
Here are the results of X’s inspection program for the first 5 days:
Day
1
2
3
4
5
Number of
restaurant units
1
1
1
1
1
Number of
quality defects
6
3
5
2
5
Help the X-Man answer the following questions:
1. What type of control chart is appropriate for this data?
2. Compute upper and lower control limits.
3. Is the process in control? Why or why not?
4. What assumptions are necessary to use your chart?
X-Man
11
The X-Man and Marvin Zindler (cont.)
Drayton was unhappy with the pace of X’s inspection program and told him to speed
it up. Here are the results for the next 2 days:
Day
6
7
Number of
restaurant units
2
4
Number of
quality defects
10
23
Add the new data to the previous sample and help the X-Man answer the following
questions:
1. What type of control chart is appropriate for the combined data set (days 1-7)?
2. Compute upper and lower control limits for the combined data set.
3. Is the process in control? Why or why not?
X-Man
12
The X-Man and the Moonshine Saki
The most popular cocktail served in Wildflour’s Cajun Sushi Bar is Moonshine Saki.
According to Billy Wagner, the Houston Chronicle’s wine critic, Moonshine Saki is an
audacious, “uniquely Cajun” interpretation of the original Japanese rice wine.
Moonshine Saki is actually a blend, composed of fermented rice and pinto beans in a
corn liquor base. The drink is served very warm, in a pint Mason jar, with a pinch of
roux, a cayenne pepper floating on top, and sporting a green onion swizzle-stick.
(Wagner recommends adding a shot of Tabasco to enhance the bouquet.)
Drayton asked X to develop a control chart to monitor quarterly sales of Moonshine
Saki. The table below shows sales in thousands of gallons for the last two years:
Year
1995
1996
Qtr.
1
2
3
4
1
2
3
4
Sales (000s)
16
19
24
22
17
21
23
21
Help the X-Man perform the following tasks:
1. Perform a seasonal adjustment of the data.
2. Use the seasonally-adjusted data to develop a control chart.
3. Interpret the behavior of the seasonally-adjusted data.
4. State the assumptions necessary to use your chart.
X-Man
13