Assignment #1: JET Copies Case Problem, taken from Taylor, B. M. (2010). Introduction to management science (10th ed.). Upper Saddle River, NJ: Pearson/Prentice Hall. Read the “JET Copies” Case Problem on pages 678-679 of the text. Using simulation estimate the loss of revenue due to copier breakdown for one year, as follows: In Excel, use a suitable method for generating the number of days needed to repair the copier, when it is out of service, according to the discrete distribution shown. In Excel, use a suitable method for simulating the interval between successive breakdowns, according to the continuous distribution shown. In Excel, use a suitable method for simulating the lost revenue for each day the copier is out of service. Put all of this together to simulate the lost revenue due to copier breakdowns over 1 year to answer the question asked in the case study. In a word processing program, write a brief description/explanation of how you implemented each component of the model. Write 1-2 paragraphs for each component of the model (days-to-repair; interval between breakdowns; lost revenue; putting it together). Answer the question posed in the case study. How confident are you that this answer is a good one? What are the limits of the study? Write at least one paragraph. There are two deliverables for this Case Problem, the Excel spreadsheet and the written description/explanation. Please submit both of them electronically via the dropbox. The assignment will be graded using the associated rubric. Outcome Assessed: Create statistical analysis of simulation results. Communicate issues in management science Grading Rubric for JET Copies Case Problem There are 12 possible points in each of the five criteria for a total of 60 points possible. Criteria 0Unacceptable(0 points) 1Developing(6 points) 2Competent(9 points) 3Exemplary(12 points) 1. Model number of days to repair Did not submit or did not model this component in an appropriate manner This component was modeled, but the method and/or implementation had mistakes that affected the validity of the model Used a method that is recognizably appropriate, but the implementation had minor mistakes Used an appropriate method and correctly implemented it 2. Model number of weeks between breakdowns Did not submit or did not model this component in an appropriate manner This component was modeled, but the method and/or implementation had mistakes that affected the validity of the model Used a method that is recognizably appropriate, but the implementation had minor mistakes Used an appropriate method and correctly implemented it 3. Model lost revenue due to breakdowns Did not submit or did not model this component in an appropriate manner This component was modeled, but the method and/or implementation had mistakes that affected the validity of the model Used a method that is recognizably appropriate, but the implementation had minor mistakes Used an appropriate method and correctly implemented it 4. Provide written description and explanation of the simulation Did not submit or described insufficiently. Omitted key points. Provided partially developed written description that matches the method 70 – 79% accuracy. Provided sufficiently developed written description that matches the method 80 – 89% accuracy. Provided fully developed written description that is correct and matches the method used with 90 – 100% accuracy. 5. Combine model components to produce a coherent answer to the question posed in the case study. (a) Answer the question posed in the case study. (b) How confident are you that this answer is a good one? (c) What are the limits of the study? Did not submit or result not provided, and/or discussed insufficiently. Provided partially correct result. Omitted discussion of confidence. Discussed limitations partially with 70 – 79% accuracy, logic, and clarity. Provided sufficiently correct result. Identified confidence and discussed limitations sufficiently with 80 – 89% accuracy, accuracy, logic, and clarity. Provided fully correct result. Identified confidence and discussed limitations fully with 90 – 100% accuracy, logic, and clarity.
Subject:
Topic:
JET Copies Case Problem
Number of sources:
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678 Cnerrrn 14 SruulerroN
36. In Chapter 8, Figure 8.6 shows a simplified project network for buildiag a house, as follo’ns:
There are four paths througfu rhis networlc
PathA: l-2-W-7
Path B: l-2-*-*-7
PathC: l–24-7
Path D: L-2-+-5-+-7
The time parameters (in weeks) defiring a triangular probahility distribution for each aaivity
are provided as follorrs:
Time Parameters
Activitf Minimum Likeliest Maximum
Using Crystal Ball, sirnulate ach path in the network and identiff the longest path (i.e., the
afticaf path).
Observing the sirnulation run frequency chart for path A, determine the probability that
this pathwill exceed the criticat path time.What does this tell you about the simulation
results for aproiect networkversus an analytical result?
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2
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3
2
4
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6-7
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t*con”)
T*o Banks was standing in line next to Robin Cole at Klecko’s
) Crllpy Center, waiting to use one of the copy machines.’Gee,
Robin, I hate this,” he said-*We have to drive all the way over here
from Southgate and then wait in line to use these copiy mactines.
I hate wasting time Iike this.”
“I knorr what you meao,” said Robin-
*Aud look who’s here. A
lot of these students are from Southgate Apartments or one of the
other apartmeots near us It seems as though it would be more
logical if lftcko’s would move its operation over to us, instead of
all of us coming over here.”
lntrodufut to Manage fiElnt Scb.roe, Tqnth Ed’tion, by Bemard W. Tayhr lll. Pnblished by Prenfce Hall. Copyight 6 2010 by P€8rson E&calion, lnc.
Iames looked around and noticed what Robin was talking
about. Robin and he were students at State Universiry and most
of the customers at Klecko’s were also students- As Robin
suggested a lot of the people waiting were State students who
lived at Southgate Apartments, where James also lived with Ernie
Moore. This gave fames an idea whidr he shared with Ernie and
their friend Terri Jones when he got home later that evening.
“Inolq you gu1lls, I’ve got an idea to make some money,’Iames
started.’Let’s open a copy business! AII we have to do is buy a
copier, put it in Terri’s duplex next door, and sell copies. I know
we crn get flrritomers because I’ve just seen them all at lCe*o’s.
If we provide a copy service right here in the Southgate complu,
we’ll make a killingl
Terri and Ernie liked the idea so the three decided to go into
the copying business. They would call it IET Copies, named for
Jameq Eroie, and Terri Their first step was to purchase a copier.
They bought one like &e one used in the college of business office
at State for $18,000. (Terri’s parents provided a len-) The com-
pany &at sold them the copier touted the copiert reliability, but
aftertheybought it, Emie talkedwithsomeone in the deaa’s office
at State,whotoldhim thatthe Univeniqy’s copierbroke down fre-
quently and when it di{ it often took between I and 4 days to get
it repaired. When Ernie told this to Terri and |ames, they became
worried. If the copier broke down frequently and was not in use
for long periods while they waited for a repair person to come fix
it they could lose a lot of revenue. As a result, Iames, Erde and
Terri thought they might need to purchase a smaller backup
copier for $8,000 to use when the main copier broke down.
However, before they approached Terri’s parents for another loan,
they waated to have an estimate of just how much money they
might lose if they did not have a backup copier. To get this esti-
mate, they decided to. develop a simulation model because they
were studying simulation in one of their classes at Sate.
To develop a simuLation model, they first needed to lnow how
frequently the copier might break dowr–specifically, the tiue
between breakdowns. No one could provide them with an exact
probability distribution, but from talking to staffmembers iu the
college of busin€sq Iames estimated that the time betrveen break-
downs was probably between 0 and 6 weeks, with the probability
increasing the longer the copier went without breaking dov’.n.
Thus, the proMbility distribution ofbreakdovms generally looked
like the following:
Cesn PnosmMs 679
Ned, thef aeeded to knorr how long it would take to get the
copier repaired when it broke dorm. They had a service contract
with the dealer that’guaranteed’prompt repir service. However,
Terri pthered some data from &e college of business from whidr
stre doeloped the fcillowing probability distribution of repair times:
nepairTime (days) Probability
I
2
3
4
Finally, they needed to estimate how mudr business theywould
lose while &e copicr was uaiting for rqpair. The three of them had
onS a vague idea of how much business they would do but finally
estimatedthattheywould sellbetween 2,0S and E 0@ copis per day
at $0.10 per copf. Hosever, they tiad no idea about vilrat kind of
probability distribution to use for thh range of values. Therefore they
decidedto use a uniform probabilitydistribution between2,000 and
8,000 copiesto estimate thenumber of copiestheywouldsellper dal.
Iames, Ernie and Tsri &cided &at if their lms of revenue due to
madrine dovmtime during I year vns $12000 or more, they should
purd,ase a backup copier. Thuq they nee&d to simulate the break-
dorrn and rqair process for a oumber of years to obtain an av€rage
annual loss of rarenue. Howwe4 before prognmming the simuhtior
model thry decided to conduct a manual simulation of thjs process for
I year to se if the model was workirg oorrectf. Perform this manual
sirmrlation for IET Copies and deermine the loss of revenue for I year.
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BpNtrrr-Cosr ANALYSTS
RrvenPnopcr
he U.S. Army Corps of Engineers has historically
dams on various rivers in the southeastern
primary iustrument for evaluating and among many
prolects under consideration is anal),sit. The CorPs
estimates both the annual deriving from a project in
several different the annual costs and then divides
bythe total costs to develop a benefit-cost ratio.
is then used by the Coqps and Crngress to compare
pmjects under consideration and select those for fund-
ing. A benefit-cost ratio greater than 1.0 indicates that the bene-
fits are greater than the costs; and the higher a project’s
benefit-cost ratio, the more likely it is to be selected over projects
lower ratios.
is waluatinga proiect to cotrstruct a dam over the
Spradlin
tified six
River in southwest Georgia. The Corps has iden-
in which benefits will accme: flood
t(x)
.43
6 x, wecks
THE SPRADLTN BLUFF thctOtAI
lntrcdudion Scionce, Tenth Editiicn, by Bemard W Taylor lll. PuHishd by Prer*ice l.lall. Copyrigrht @ 2010 by Pearson Education,
