Paper Assignment
Quantitative Analysis for Management
Thirteenth Edition
Chapter 3
Decision Analysis
Copyright © 2018, 2015, 2012 Pearson Education, Inc. All Rights Reserved.
Copyright © 2018, 2015, 2012 Pearson Education, Inc. All Rights Reserved.
Learning Outcomes
Evaluate uncertainty and risk in business decisions.
Design and utilize Microsoft Excel formulas to conduct basic as well as advanced statistical computations.
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Introduction
What is involved in making a good decision?
Decision theory is an analytic and systematic approach to the study of decision making
A good decision is one that is based on logic, considers all available data and possible alternatives, and applies a quantitative approach
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THE SIX STEPS IN DECISION MAKING
Clearly define the problem at hand
List the possible alternatives
Identify the possible outcomes or states of nature
List the payoff (typically profit) of each combination of alternatives and outcomes
Select one of the mathematical decision theory models
Apply the model and make your decision
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Thompson Lumber Company (1 of 3)
Step 1 – Define the problem
Consider expanding by manufacturing and marketing a new product – backyard storage sheds
Step 2 – List alternatives
Construct a large new plant
Construct a small new plant
Do not develop the new product line
Step 3 – Identify possible outcomes, states of nature
The market could be favorable or unfavorable
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Thompson Lumber Company (2 of 3)
Step 4 – List the payoffs
Identify conditional values for the profits for large plant, small plant, and no development for the two possible market conditions
Step 5 – Select the decision model
Depends on the environment and amount of risk and uncertainty
Step 6 – Apply the model to the data
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Thompson Lumber Company (3 of 3)
TABLE 3.1 Decision Table with Conditional Values for Thompson Lumber
| STATE OF NATURE |
| Blank | FAVORABLE MARKET | UNFAVORABLE MARKET |
| ALTERNATIVE | ($) | ($) |
| Construct a large plant | 200,000 | −180,000 |
| Construct a small plant | 100,000 | −20,000 |
| Do nothing | 0 | 0 |
Note: It is important to include all alternatives, including “do nothing.”
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TYPES OF DECISION-MAKING ENVIRONMENTS
Decision making under certainty
The decision maker knows with certainty the consequences of every alternative or decision choice
Decision making under uncertainty
The decision maker does not know the probabilities of the various outcomes
Decision making under risk
The decision maker knows the probabilities of the various outcomes
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DECISION MAKING UNDER UNCERTAINTY
Criteria for making decisions under uncertainty
Maximax (optimistic)
Maximin (pessimistic)
Criterion of realism (Hurwicz)
Equally likely (Laplace)
Minimax regret
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9
Optimistic
Used to find the alternative that maximizes the maximum payoff – maximax criterion
Locate the maximum payoff for each alternative
Select the alternative with the maximum number
TABLE 3.2 Thompson’s Maximax Decision
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE | MAXIMUM IN |
| Blank | MARKET | MARKET | A ROW |
| ALTERNATIVE | ($) | ($) | ($) |
| Construct a large plant | 200,000 | −180,000 | 200,000 |
| Blank | Blank | Blank | Maximax |
| Construct a small plant | 100,000 | −20,000 | 100,000 |
| Do nothing | 0 | 0 | 0 |
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10
Pessimistic
Used to find the alternative that maximizes the minimum payoff – maximin criterion
Locate the minimum payoff for each alternative
Select the alternative with the maximum number
TABLE 3.3 Thompson’s Maximin Decision
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE | MAXIMUM IN |
| Blank | MARKET | MARKET | A ROW |
| ALTERNATIVE | ($) | ($) | ($) |
| Construct a large plant | 200,000 | −180,000 | −180,000 |
| Construct a small plant | 100,000 | −20,000 | −20,000 |
| Do nothing | 0 | 0 | 0 |
| Blank | Blank | Blank | Maximin |
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11
Criterion of Realism (Hurwicz) (1 of 2)
Often called weighted average
Compromise between optimism and pessimism
Select a coefficient of realism α, with 0 ≤ α ≤ 1
α = 1 is perfectly optimistic
α = 0 is perfectly pessimistic
Compute the weighted averages for each alternative
Select the alternative with the highest value
Weighted average = α(best in row)
+ (1−α)(worst in row)
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12
Criterion of Realism (Hurwicz) (2 of 2)
For the large plant alternative using α = 0.8
(0.8)(200,000) + (1−0.8)(−180,000) = 124,000
For the small plant alternative using α = 0.8
(0.8)(100,000) + (1−0.8)(−20,000) = 76,000
TABLE 3.4 Thompson’s Criterion of Realism Decision
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE | CRITERION OF REALISM |
| Blank | MARKET | MARKET | OR WEIGHTED AVERAGE |
| ALTERNATIVE | ($) | ($) | (α = 0.8) ($) |
| Construct a large plant | 200,000 | −180,000 | 124,000 |
| Blank | Blank | Blank | Realism |
| Construct a small plant | 100,000 | −20,000 | 76,000 |
| Do nothing | 0 | 0 | 0 |
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13
Equally Likely (Laplace)
Considers all the payoffs for each alternative
Find the average payoff for each alternative
Select the alternative with the highest average
TABLE 3.5 Thompson’s Equally Likely Decision
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE | Blank |
| Blank | MARKET | MARKET | ROW AVERAGE |
| ALTERNATIVE | ($) | ($) | ($) |
| Construct a large plant | 200,000 | −180,000 | 10,000 |
| Construct a small plant | 100,000 | −20,000 | 40,000 |
| Blank | Blank | Blank | Equally likely |
| Do nothing | 0 | 0 | 0 |
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14
Minimax Regret (1 of 4)
Based on opportunity loss or regret
The difference between the optimal profit and actual payoff for a decision
Create an opportunity loss table by determining the opportunity loss from not choosing the best alternative
Calculate opportunity loss by subtracting each payoff in the column from the best payoff in the column
Find the maximum opportunity loss for each alternative and pick the alternative with the minimum number
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15
Minimax Regret (2 of 4)
TABLE 3.6 Determining Opportunity Losses for Thompson Lumber
| STATE OF NATURE |
| FAVORABLE | UNFAVORABLE |
| MARKET | MARKET |
| ($) | ($) |
| 200,000 − 200,000 | 0 − (−180,000) |
| 200,000 − 100,000 | 0 − (−20,000) |
| 200,000 − 0 | 0 − 0 |
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16
Minimax Regret (3 of 4)
TABLE 3.7 Opportunity Loss Table for Thompson Lumber
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE |
| Blank | MARKET | MARKET |
| ALTERNATIVE | ($) | ($) |
| Construct a large plant | 0 | 180,000 |
| Construct a small plant | 100,000 | 20,000 |
| Do nothing | 200,000 | 0 |
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Minimax Regret (4 of 4)
TABLE 3.8 Thompson’s Minimax Decision Using Opportunity Loss
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE | MAXIMUM IN |
| Blank | MARKET | MARKET | A ROW |
| ALTERNATIVE | ($) | ($) | ($) |
| Construct a large plant | 0 | 180,000 | 180,000 |
| Construct a small plant | 100,000 | 20,000 | 100,000 |
| Blank | Blank | Blank | Minimax |
| Do nothing | 200,000 | 0 | 200,000 |
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18
DECISION MAKING UNDER RISK (1 OF 2)
When there are several possible states of nature and the probabilities associated with each possible state are known
Most popular method – choose the alternative with the highest expected monetary value (EMV)
where
Xi = payoff for the alternative in state of nature i
P(Xi) = probability of achieving payoff Xi (i.e., probability of state of nature i)
∑ = summation symbol
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Decision Making Under Risk (2 of 2)
Expanding the equation
EMV (alternative i) = (payoff of first state of nature)
×(probability of first state of nature)
+ (payoff of second state of nature)
×(probability of second state of nature)
+ … + (payoff of last state of nature)
×(probability of last state of nature)
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20
EMV for Thompson Lumber (1 of 2)
Each market outcome has a probability of occurrence of 0.50
Which alternative would give the highest EMV?
EMV (large plant) = ($200,000)(0.5) + (−$180,000)(0.5)
= $10,000
EMV (small plant) = ($100,000)(0.5) + (−$20,000)(0.5)
= $40,000
EMV (do nothing) = ($0)(0.5) + ($0)(0.5)
= $0
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EMV for Thompson Lumber (2 of 2)
TABLE 3.9 Decision Table with Probabilities and EMVs for Thompson Lumber
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE | Blank |
| Blank | MARKET | MARKET | Blank |
| ALTERNATIVE | ($) | ($) | EMV ($) |
| Construct a large plant | 200,000 | −180,000 | 10,000 |
| Construct a small plant | 100,000 | −20,000 | 40,000 |
| Blank | Blank | Blank | Best EMV |
| Do nothing | 0 | 0 | 0 |
| Probabilities | 0.50 | 0.50 | Blank |
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Expected Value of Perfect Information (EVPI) (1 of 6)
EVPI places an upper bound on what you should pay for additional information
EVwPI is the long run average return if we have perfect information before a decision is made
EVwPI = ∑(best payoff in state of nature i)
(probability of state of nature i)
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Expected Value of Perfect Information (EVPI) (2 of 6)
Expanded EVwPI becomes
EVwPI = (best payoff for first state of nature)
× (probability of first state of nature)
+ (best payoff for second state of nature)
× (probability of second state of nature)
+ … + (best payoff for last state of nature)
× (probability of last state of nature)
And
EVPI = EVwPI − Best EMV
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Expected Value of Perfect Information (EVPI) (3 of 6)
Scientific Marketing, Inc. offers analysis that will provide certainty about market conditions (favorable)
Additional information will cost $65,000
Should Thompson Lumber purchase the information?
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Expected Value of Perfect Information (EVPI) (4 of 6)
TABLE 3.10 Decision Table with Perfect Information
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE | Blank |
| Blank | MARKET | MARKET | Blank |
| ALTERNATIVE | ($) | ($) | EMV ($) |
| Construct a large plant | 200,000 | −180,000 | 10,000 |
| Construct a small plant | 100,000 | −20,000 | 40,000 |
| Do nothing | 0 | 0 | 0 |
| With perfect information | 200,000 | 0 | 100,000 |
| Blank | Blank | Blank | EVwPI |
| Probabilities | 0.50 | 0.50 | Blank |
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Expected Value of Perfect Information (EVPI) (5 of 6)
The maximum EMV without additional information is $40,000
Therefore
EVPI = EVwPI − Maximum EMV
= $100,000 − $40,000
= $60,000
So the maximum Thompson should pay for the additional information is $60,000
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Expected Value of Perfect Information (EVPI) (6 of 6)
The maximum EMV without additional information is $40,000
Therefore
EVPI = EVwPI − Maximum EMV
= $100,000 − $40,000
= $60,000
Thompson should not pay $65,000 for this information
So the maximum Thompson should pay for the additional information is $60,000
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Expected Opportunity Loss (1 of 2)
Expected opportunity loss (EOL) is the cost of not picking the best solution
Construct an opportunity loss table
For each alternative, multiply the opportunity loss by the probability of that loss for each possible outcome and add these together
Minimum EOL will always result in the same decision as maximum EMV
Minimum EOL will always equal EVPI
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Expected Opportunity Loss (2 of 2)
EOL (large plant) = (0.50)($0) + (0.50)($180,000) = $90,000
EOL (small plant) = (0.50)($100,000) + (0.50)($20,000) = $60,000
EOL (do nothing) = (0.50)($200,000) + (0.50)($0) = $100,000
TABLE 3.11 EOL Table for Thompson Lumber
| STATE OF NATURE |
| Blank | FAVORABLE | UNFAVORABLE | Blank |
| Blank | MARKET | MARKET | Blank |
| ALTERNATIVE | ($) | ($) | EOL ($) |
| Construct a large plant | 0 | 180,000 | 90,000 |
| Construct a small plant | 100,000 | 20,000 | 60,000 |
| Blank | Blank | Blank | Best EOL |
| Do nothing | 200,000 | 0 | 100,000 |
| Probabilities | 0.50 | 0.50 | Blank |
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Sensitivity Analysis (1 of 4)
Define P = probability of a favorable market
EMV(large plant) = $200,000P − $180,000)(1 − P)
= $200,000P − $180,000 + $180,000P
= $380,000P − $180,000
EMV(small plant) = $100,000P − $20,000)(1 − P)
= $100,000P − $20,000 + $20,000P
= $120,000P − $20,000
EMV(do nothing) = $0P + 0(1 − P)
= $0
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Sensitivity Analysis (2 of 4)
FIGURE 3.1 Sensitivity Analysis
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Sensitivity Analysis (3 of 4)
Point 1: EMV(do nothing) = EMV(small plant)
Point 2: EMV(small plant) = EMV(large plant)
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Sensitivity Analysis (4 of 4)
FIGURE 3.1 Sensitivity Analysis
| BEST ALTERNATIVE | RANGE OF P VALUES |
| Do nothing | Less than 0.167 |
| Construct a small plant | 0.167 − 0.615 |
| Construct a large plant | Greater than 0.615 |
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A Minimization Example (1 of 8)
Three year lease for a copy machine
Which machine should be selected?
TABLE 3.12 Payoff Table with Monthly Copy Costs for Business Analytics Department
| Blank | 10,000 COPIES PER MONTH | 20,000 COPIES PER MONTH | 30,000 COPIES PER MONTH |
| Machine A | 950 | 1,050 | 1,150 |
| Machine B | 850 | 1,100 | 1,350 |
| Machine C | 700 | 1,000 | 1,300 |
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A Minimization Example (2 of 8)
Three year lease for a copy machine
Which machine should be selected?
TABLE 3.13 Best and Worst Payoffs (Costs) for Business Analytics Department
| Blank | 10,000 COPIES PER MONTH | 20,000 COPIES PER MONTH | 30,000 COPIES PER MONTH | BEST PAYOFF (MINIMUM) | WORST PAYOFF (MAXIMUM) |
| Machine A | 950 | 1,050 | 1,150 | 950 | 1,150 |
| Machine B | 850 | 1,100 | 1,350 | 850 | 1,350 |
| Machine C | 700 | 1,000 | 1,300 | 700 | 1,300 |
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A Minimization Example (3 of 8)
Using Hurwicz criteria with 70% coefficient
Weighted average = 0.7(best payoff)
+ (1 − 0.7)(worst payoff)
For each machine
Machine A: 0.7(950) + 0.3(1,150) = 1,010
Machine B: 0.7(850) + 0.3(1,350) = 1,000
Machine C: 0.7(700) + 0.3(1,300) = 880
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A Minimization Example (4 of 8)
For equally likely criteria
For each machine
Machine A: (950 + 1,050 + 1,150)÷3 = 1,050
Machine B: (850 + 1,100 + 1,350)÷3 = 1,100
Machine C: (700 + 1,000 + 1,300)÷3 = 1,000
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A Minimization Example (5 of 8)
For EMV criteria
| USAGE | PROBABILITY |
| 10,000 | 0.40 |
| 20,000 | 0.30 |
| 30,000 | 0.30 |
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A Minimization Example (6 of 8)
For EMV criteria
TABLE 3.14 Expected Monetary Values and Expected Values with Perfect Information for Business Analytics Department
| Blank | 10,000 COPIES PER MONTH | 20,000 COPIES PER MONTH | 30,000 COPIES PER MONTH | EMV |
| Machine A | 950 | 1,050 | 1,150 | 1,040 |
| Machine B | 850 | 1,100 | 1,350 | 1,075 |
| Machine C | 700 | 1,000 | 1,300 | 970 |
| With perfect information | 700 | 1,000 | 1,150 | 925 |
| Probability | 0.4 | 0.3 | 0.3 | Blank |
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A Minimization Example (7 of 8)
For EVPI
TABLE 3.14 Expected Monetary Values and Expected Values with Perfect Information for Business Analytics Department
| Blank | 10,000 COPIES PER MONTH | 20,000 COPIES PER MONTH | 30,000 COPIES PER MONTH | EMV |
| Machine A | 950 | 1,050 | 1,150 | 1,040 |
| Machine B | 850 | 1,100 | 1,350 | 1,075 |
| Machine C | 700 | 1,000 | 1,300 | 970 |
| With perfect information | 700 | 1,000 | 1,150 | 925 |
| Probability | 0.4 | 0.3 | 0.3 | Blank |
EVwPI = $925
Best EMV without perfect information = $970
EVPI = 970 − 925 = $45
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A Minimization Example (8 of 8)
Opportunity loss criteria
TABLE 3.15 Opportunity Loss Table for Business Analytics Department
| Blank | 10,000 COPIES PER MONTH | 20,000 COPIES PER MONTH | 30,000 COPIES PER MONTH | MAXIMUM | EOL |
| Machine A | 250 | 50 | 0 | 250 | 115 |
| Machine B | 150 | 100 | 200 | 200 | 150 |
| Machine C | 0 | 0 | 150 | 150 | 45 |
| Probability | 0.4 | 0.3 | 0.3 | Blank | Blank |
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Using Excel (1 of 2)
PROGRAM 3.2A Excel QM Results for Thompson Lumber Example
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Using Excel (2 of 2)
PROGRAM 3.2B Key Formulas in Excel QM for Thompson Lumber Example
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IN-CLASS EXERCISE
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Summary
Evaluated uncertainty and risk in business decisions.
Designed and utilized Microsoft Excel formulas to conduct basic as well as advanced statistical computations.
© 2012 Pearson Prentice Hall. All rights reserved.
Copyright © 2018, 2015, 2012 Pearson Education, Inc. All Rights Reserved.
46
EXTRA MATERIAL
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DECISION TREES
Any problem that can be presented in a decision table can be graphically represented in a decision tree
Most beneficial when a sequence of decisions must be made
All decision trees contain decision points/nodes and state-of-nature points/nodes
At decision nodes one of several alternatives may be chosen
At state-of-nature nodes one state of nature will occur
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Five Steps of Decision Tree Analysis
Define the problem
Structure or draw the decision tree
Assign probabilities to the states of nature
Estimate payoffs for each possible combination of alternatives and states of nature
Solve the problem by computing expected monetary values (EMVs) for each state of nature node
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Structure of Decision Trees
Trees start from left to right
Trees represent decisions and outcomes in sequential order
Squares represent decision nodes
Circles represent states of nature nodes
Lines or branches connect the decisions nodes and the states of nature
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Thompson’s Decision Tree (1 of 2)
FIGURE 3.2 Thompson’s Decision Tree
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Thompson’s Decision Tree (2 of 2)
FIGURE 3.3 Completed and Solved Decision Tree for Thompson Lumber
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Thompson’s Complex Decision Tree (1 of 5)
FIGURE 3.4 Larger Decision Tree with Payoffs and Probabilities for Thompson Lumber
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Thompson’s Complex Decision Tree (2 of 5)
Given favorable survey results
EMV(node 2) = EMV(large plant | positive survey)
= (0.78)($190,000) + (0.22)(−$190,000) = $106,400
EMV(node 3) = EMV(small plant | positive survey)
= (0.78)($90,000) + (0.22)(−$30,000)
= $63,600
EMV for no plant = −$10,000
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Thompson’s Complex Decision Tree (3 of 5)
Given negative survey results
EMV(node 4) = EMV(large plant | negative survey)
= (0.27)($190,000) + (0.73)(−$190,000)
= −$87,400
EMV(node 5) = EMV(small plant | negative survey)
= (0.27)($90,000) + (0.73)(−$30,000)
= $2,400
EMV for no plant = −$10,000
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Thompson’s Complex Decision Tree (4 of 5)
Expected value of the market survey
EMV(node 1) = EMV(conduct survey)
= (0.45)($106,400) + (0.55)($2,400)
= $47,880 + $1,320 = $49,200
Expected value no market survey
EMV(node 6) = EMV(large plant)
= (0.50)($200,000) + (0.50)(−$180,000)
= $10,000
EMV(node 7) = EMV(small plant)
= (0.50)($100,000) + (0.50)(−$20,000)
= $40,000
EMV for no plant = $0
The best choice is to seek marketing information
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Thompson’s Complex Decision Tree (5 of 5)
FIGURE 3.5 Thompson’s Decision Tree with EMVs Shown
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Expected Value of Sample Information
Thompson wants to know the actual value of doing the survey
= (EV with SI + cost) − (EV without SI)
EVSI = ($49,200 + $10,000) − $40,000 = $19,200
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Efficiency of Sample Information
Possibly many types of sample information available
Different sources can be evaluated
For Thompson
Market survey is only 32% as efficient as perfect information
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Sensitivity Analysis (1 of 2)
How sensitive are the decisions to changes in the probabilities?
How sensitive is our decision to the probability of a favorable survey result?
If the probability of a favorable result (p = .45) were to change, would we make the same decision?
How much could it change before we would make a different decision?
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Sensitivity Analysis (2 of 2)
p = probability of a favorable survey result
(1−p) = probability of a negative survey result
EMV(node 1) = ($106,400)p +($2,400)(1−p)
= $104,000p + $2,400
We are indifferent when the EMV of node 1 is the same as the EMV of not conducting the survey
$104,000p + $2,400 = $40,000
$104,000p = $37,600
p = $37,600÷$104,000 = 0.36
If p < 0.36, do not conduct the survey
If p > 0.36, conduct the survey
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Bayesian Analysis
Many ways of getting probability data
Management’s experience and intuition
Historical data
Computed from other data using Bayes’ theorem
Bayes’ theorem incorporates initial estimates and information about the accuracy of the sources
Allows the revision of initial estimates based on new information
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Calculating Revised Probabilities (1 of 7)
Four conditional probabilities for Thompson Lumber
P(favorable market(FM) | survey results positive) = 0.78
P(unfavorable market(UM) | survey results positive) = 0.22
P(favorable market(FM) | survey results negative) = 0.27
P(unfavorable market(UM) | survey results negative) = 0.73
Prior probabilities
P(FM) = 0.50
P(UM) = 0.50
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Calculating Revised Probabilities (2 of 7)
TABLE 3.16 Market Survey Reliability in Predicting States of Nature
| STATE OF NATURE |
| Blank | FAVORABLE MARKET | UNFAVORABLE MARKET |
| RESULT OF SURVEY | (FM) | (UM) |
| Positive (predicts favorable market for product) | P (survey positive | FM) = 0.70 | P (survey positive | UM = 0.20 |
| Negative (predicts unfavorable market for product) | P (survey negative | FM) = 0.30 | P (survey negative | UM) = 0.80 |
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Calculating Revised Probabilities (3 of 7)
Calculating posterior probabilities
where
A, B = any two events
A’ = complement of A
A = favorable market
B = positive survey
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Calculating Revised Probabilities (4 of 7)
P(FM | survey positive)
P(UM | survey positive)
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Calculating Revised Probabilities (5 of 7)
TABLE 3.17 Probability Revisions Given a Positive Survey
| POSTERIOR PROBABILITY |
| STATE OF NATURE | CONDITIONAL PROBABILITY P(SURVEY POSITIVE | STATE OF NATURE) | PRIOR PROBABILITY | JOINT PROBABILITY | P(STATE OF NATURE | SURVEY POSITIVE) | |||
| FM | 0.70 | × 0.50 | = | 0.35 | Blank | 0.35÷0.45 = | 0.78 |
| UM | 0.20 | × 0.50 | = | 0.10 | Blank | 0.10÷0.45 = | 0.22 |
| Blank | Blank | P(survey results positive) | = | 0.45 | Blank | Blank | 1.00 |
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Calculating Revised Probabilities (6 of 7)
P(FM | survey negative)
P(UM | survey negative)
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Calculating Revised Probabilities (7 of 7)
TABLE 3.18 Probability Revisions Given a Negative Survey
| POSTERIOR PROBABILITY |
| STATE OF NATURE | CONDITIONAL PROBABILITY P(SURVEY NEGATIVE | STATE OF NATURE) | PRIOR PROBABILITY | JOINT PROBABILITY | P(STATE OF NATURE | SURVEY NEGATIVE) | |||
| FM | 0.30 | × 0.50 | = | 0.15 | Blank | 0.15÷0.55 = | 0.27 |
| UM | 0.80 | × 0.50 | = | 0.40 | Blank | 0.40÷0.55 = | 0.73 |
| Blank | Blank | P(survey results negative) | = | 0.55 | Blank | Blank | 1.00 |
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Using Excel (1 of 2)
PROGRAM 3.3A Results of Bayes’ Calculations in Excel 2016
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Using Excel (2 of 2)
PROGRAM 3.3B Formulas Used for Bayes’ Calculations in Excel 2016
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Potential Problems Using Survey Results
We can not always get the necessary data for analysis
Survey results may be based on cases where an action was taken
Conditional probability information may not be as accurate as we would like
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UTILITY THEORY (1 OF 5)
Monetary value is not always a true indicator of the overall value of the result of a decision
The overall value of a decision is called utility
Economists assume that rational people make decisions to maximize their utility
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Utility Theory (2 of 5)
FIGURE 3.6 Your Decision Tree for the Lottery Ticket
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Utility Theory (3 of 5)
Utility assessment assigns the worst outcome a utility of 0 and the best outcome a utility of 1
A standard gamble is used to determine utility values
When you are indifferent, your utility values are equal
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Utility Theory (4 of 5)
FIGURE 3.7 Standard Gamble for Utility Assessment
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Utility Theory (5 of 5)
Expected utility of alternative 2
= Expected utility of alternative 1
Utility of other outcome
= (p)(utility of best outcome, which is 1)
+ (1−p)(utility of the worst outcome, which is 0)
Utility of other outcome
= (p)(1) + (1−p)(0) = p
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Investment Example (1 of 3)
Construct a utility curve revealing preference for money between $0 and $10,000
A utility curve plots the utility value versus the monetary value
An investment in a bank will result in $5,000
An investment in real estate will result in $0 or $10,000
Unless there is an 80% chance of getting $10,000 from the real estate deal, prefer to have her money in the bank
If p = 0.80, Jane is indifferent between the bank or the real estate investment
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Investment Example (2 of 3)
FIGURE 3.8 Utility of $5,000
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Investment Example (3 of 3)
Assess other utility values
Utility for $7,000 = 0.90
Utility for $3,000 = 0.50
Use the three different dollar amounts and assess utilities
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Utility Curve (1 of 2)
FIGURE 3.9 Utility Curve for Jane Dickson
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Utility Curve (2 of 2)
Typical of a risk avoider
Less utility from greater risk
Avoids situations where high losses might occur
As monetary value increases, utility curve increases at a slower rate
A risk seeker gets more utility from greater risk
As monetary value increases, the utility curve increases at a faster rate
Risk indifferent gives a linear utility curve
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Preferences for Risk
FIGURE 3.10 Preferences for Risk
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Utility as a Decision-Making Criteria (1 of 6)
Once a utility curve has been developed it can be used in making decisions
Replaces monetary outcomes with utility values
Expected utility is computed instead of the EMV
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Utility as a Decision-Making Criteria (2 of 6)
Mark Simkin loves to gamble
A game tossing thumbtacks in the air
If the thumbtack lands point up, Mark wins $10,000
If the thumbtack lands point down, Mark loses $10,000
Mark believes that there is a 45% chance the thumbtack will land point up
Should Mark play the game (alternative 1)?
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Utility as a Decision-Making Criteria (3 of 6)
FIGURE 3.11 Decision Facing Mark Simkin
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Utility as a Decision-Making Criteria (4 of 6)
Step 1– Define Mark’s utilities
U(−$10,000) = 0.05
U($0) = 0.15
U($10,000) = 0.30
FIGURE 3.12 Utility Curve for Mark Simkin
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Utility as a Decision-Making Criteria (5 of 6)
Step 2 – Replace monetary values with utility values
E(alternative 1: play the game) = (0.45)(0.30) + (0.55)(0.05)
= 0.135 + 0.027 = 0.162
E(alternative 2: don’t play the game) = 0.15
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Utility as a Decision-Making Criteria (6 of 6)
FIGURE 3.13 Using Expected Utilities in Decision Making
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Copyright
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90
ii
XPX
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EMValternative=
=-
0$120,000$20,000
P
==
20,000
0.167
120,000
P
$120,000P−$20,000=$380,000P−$180,000
$120,000P-$20,000=$380,000P-$180,000
P = 160,000 260,000
=0.615
P=
160,000
260,000
=0.615
Expected valueExpected value of best
sampledecisionsample
informationinformation
withwit
EV
hout
SI
æöæö
ç÷ç÷
=
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EVSI
Efficiency of sample information = 100%
EVPI
19,200
Efficiency of sample information = 100%
= 32%
60,000
()()
()
()()()()
PB|APA
PA|B
PB|APAPB|APA
´
=
¢¢
´+´
(survey positive|FM)(FM)
(survey positive|FM)(FM)(survey positive
|UM)(UM)
(0.70)(0.50)0.35
0.78
(0.70)(0.50)+(0.20)(0.50)0.45
PP
P PPP
=
+
===
= P(survey positive |UM)P(UM)
P(survey positive |UM)P(UM)+ P(survey positive |FM)P(FM)
= (0.20)(0.50)
(0.20)(0.50)+(0.70)(0.50) =
0.10 0.45
= 0.22
=
P(survey positive|UM)P(UM)
P(survey positive |UM)P(UM)+P(survey positive |FM)P(FM)
=
(0.20)(0.50)
(0.20)(0.50)+(0.70)(0.50)
=
0.10
0.45
=0.22
(survey negative|FM)(FM)
(survey negativeFM)(FM)(survey negative
UM)(UM)
(0.30)(0.50)0.15
0.27
(0.30)(0.50)+(0.80)(0.50)0.55
PP
P |PP|P
=
+
===
(survey negative|UM)(UM)
(survey negative|UM)(UM)(survey negative
|FM)(FM)
(0.80)(0.50)0.40
0.73
(0.80)(0.50)+(0.30)(0.50)0.55
PP
P PPP
=
+
===