online test chapters
Chapter 3
To accompany
Quantitative Analysis for Management, Eleventh Edition, by Render, Stair, and Hanna
Power Point slides created by Brian Peterson
Decision Analysis
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
*
Learning Objectives
List the steps of the decision-making process.
Describe the types of decision-making environments.
Make decisions under uncertainty.
Use probability values to make decisions under risk.
After completing this chapter, students will be able to:
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Learning Objectives
Develop accurate and useful decision trees.
Revise probabilities using Bayesian analysis.
Use computers to solve basic decision-making problems.
Understand the importance and use of utility theory in decision making.
After completing this chapter, students will be able to:
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Chapter Outline
3.1 Introduction
3.2 The Six Steps in Decision Making
3.3 Types of Decision-Making Environments
3.4 Decision Making under Uncertainty
3.5 Decision Making under Risk
3.6 Decision Trees
3.7 How Probability Values Are Estimated by Bayesian Analysis
3.8 Utility Theory
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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 the quantitative approach described here.
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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
Step 1 – Define the problem.
- The company is considering 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 at all.
Step 3 – Identify possible outcomes.
- The market could be favorable or unfavorable.
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Thompson Lumber Company
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.
- This depends on the environment and amount of risk and uncertainty.
Step 6 – Apply the model to the data.
- Solution and analysis are then used to aid in decision-making.
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Thompson Lumber Company
Table 3.1
Decision Table with Conditional Values for Thompson Lumber
| STATE OF NATURE | ||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) |
| Construct a large plant | 200,000 | –180,000 |
| Construct a small plant | 100,000 | –20,000 |
| Do nothing | 0 | 0 |
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Types of Decision-Making Environments
Type 1: Decision making under certainty
- The decision maker knows with certainty the consequences of every alternative or decision choice.
Type 2: Decision making under uncertainty
- The decision maker does not know the probabilities of the various outcomes.
Type 3: Decision making under risk
- The decision maker knows the probabilities of the various outcomes.
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Decision Making Under Uncertainty
Maximax (optimistic)
Maximin (pessimistic)
Criterion of realism (Hurwicz)
Equally likely (Laplace)
Minimax regret
There are several criteria for making decisions under uncertainty:
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Maximax
Used to find the alternative that maximizes the maximum payoff.
- Locate the maximum payoff for each alternative.
- Select the alternative with the maximum number.
Table 3.2
| STATE OF NATURE | |||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) | MAXIMUM IN A ROW ($) |
| Construct a large plant | 200,000 | –180,000 | 200,000 |
| Construct a small plant | 100,000 | –20,000 | 100,000 |
| Do nothing | 0 | 0 | 0 |
Maximax
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Maximin
Used to find the alternative that maximizes the minimum payoff.
- Locate the minimum payoff for each alternative.
- Select the alternative with the maximum number.
Table 3.3
| STATE OF NATURE | |||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) | MINIMUM IN A ROW ($) |
| 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 |
Maximin
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Criterion of Realism (Hurwicz)
This is a weighted average compromise between optimism and pessimism.
- Select a coefficient of realism , with 0≤α≤1.
- A value of 1 is perfectly optimistic, while a value of 0 is perfectly pessimistic.
- Compute the weighted averages for each alternative.
- Select the alternative with the highest value.
Weighted average = (maximum in row)
+ (1 – )(minimum in row)
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Criterion of Realism (Hurwicz)
- For the large plant alternative using = 0.8:
(0.8)(200,000) + (1 – 0.8)(–180,000) = 124,000 - For the small plant alternative using = 0.8:
(0.8)(100,000) + (1 – 0.8)(–20,000) = 76,000
Table 3.4
| STATE OF NATURE | |||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) | CRITERION OF REALISM ( = 0.8) $ |
| Construct a large plant | 200,000 | –180,000 | 124,000 |
| Construct a small plant | 100,000 | –20,000 | 76,000 |
| Do nothing | 0 | 0 | 0 |
Realism
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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
| STATE OF NATURE | |||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) | ROW AVERAGE ($) |
| Construct a large plant | 200,000 | –180,000 | 10,000 |
| Construct a small plant | 100,000 | –20,000 | 40,000 |
| Do nothing | 0 | 0 | 0 |
Equally likely
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Minimax Regret
Based on opportunity loss or regret, this is the difference between the optimal profit and actual payoff for a decision.
- Create an opportunity loss table by determining the opportunity loss from not choosing the best alternative.
- Opportunity loss is calculated by subtracting each payoff in the column from the best payoff in the column.
- Find the maximum opportunity loss for each alternative and pick the alternative with the minimum number.
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Minimax Regret
Table 3.6
Determining Opportunity Losses for Thompson Lumber
| STATE OF NATURE | |
| FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) |
| 200,000 – 200,000 | 0 – (–180,000) |
| 200,000 – 100,000 | 0 – (–20,000) |
| 200,000 – 0 | 0 – 0 |
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Minimax Regret
Table 3.7
Opportunity Loss Table for Thompson Lumber
| STATE OF NATURE | ||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) |
| Construct a large plant | 0 | 180,000 |
| Construct a small plant | 100,000 | 20,000 |
| Do nothing | 200,000 | 0 |
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Minimax Regret
Table 3.8
Thompson’s Minimax Decision Using Opportunity Loss
| STATE OF NATURE | |||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) | MAXIMUM IN A ROW ($) |
| Construct a large plant | 0 | 180,000 | 180,000 |
| Construct a small plant | 100,000 | 20,000 | 100,000 |
| Do nothing | 200,000 | 0 | 200,000 |
Minimax
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Decision Making Under Risk
- This is decision making when there are several possible states of nature, and the probabilities associated with each possible state are known.
- The most popular method is to choose the alternative with the highest expected monetary value (EMV).
- This is very similar to the expected value calculated in the last chapter.
EMV (alternative i) = (payoff of first state of nature)
x (probability of first state of nature)
+ (payoff of second state of nature)
x (probability of second state of nature)
+ … + (payoff of last state of nature)
x (probability of last state of nature)
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EMV for Thompson Lumber
- Suppose each market outcome has a probability of occurrence of 0.50.
- Which alternative would give the highest EMV?
- The calculations are:
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)
= $0
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EMV for Thompson Lumber
Table 3.9
| STATE OF NATURE | |||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) | EMV ($) |
| 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 |
| Probabilities | 0.50 | 0.50 |
Largest EMV
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Expected Value of Perfect Information (EVPI)
- EVPI places an upper bound on what you should pay for additional information.
EVPI = EVwPI – Maximum EMV
- EVwPI is the long run average return if we have perfect information before a decision is made.
EVwPI = (best payoff for first state of nature)
x (probability of first state of nature)
+ (best payoff for second state of nature)
x (probability of second state of nature)
+ … + (best payoff for last state of nature)
x (probability of last state of nature)
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Expected Value of Perfect Information (EVPI)
- Suppose Scientific Marketing, Inc. offers analysis that will provide certainty about market conditions (favorable).
- Additional information will cost $65,000.
- Should Thompson Lumber purchase the information?
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Expected Value of Perfect Information (EVPI)
Table 3.10
Decision Table with Perfect Information
| STATE OF NATURE | |||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) | EMV ($) |
| 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 |
| Probabilities | 0.5 | 0.5 |
EVwPI
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Expected Value of Perfect Information (EVPI)
The maximum EMV without additional information is $40,000.
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)
The maximum EMV without additional information is $40,000.
EVPI = EVwPI – Maximum EMV
= $100,000 - $40,000
= $60,000
Therefore, 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
- Expected opportunity loss (EOL) is the cost of not picking the best solution.
- First 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
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)
= $100,000
Table 3.11
| STATE OF NATURE | |||
| ALTERNATIVE | FAVORABLE MARKET ($) | UNFAVORABLE MARKET ($) | EOL |
| Construct a large plant | 0 | 180,000 | 90,000 |
| Construct a small plant | 100,000 | 20,000 | 60,000 |
| Do nothing | 200,000 | 0 | 100,000 |
| Probabilities | 0.50 | 0.50 |
Minimum EOL
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Sensitivity Analysis
- Sensitivity analysis examines how the decision might change with different input data.
- For the Thompson Lumber example:
P = probability of a favorable market
(1 – P) = probability of an unfavorable market
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Sensitivity Analysis
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
EMV (do nothing)
Figure 3.1
$300,000
$200,000
$100,000
0
–$100,000
–$200,000
EMV Values
EMV (large plant)
EMV (small plant)
Point 1
Point 2
.167
.615
1
Values of P
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Sensitivity Analysis
Point 1:
EMV(do nothing) = EMV(small plant)
Point 2:
EMV(small plant) = EMV(large plant)
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Sensitivity Analysis
Figure 3.1
| 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 |
$300,000
$200,000
$100,000
0
–$100,000
–$200,000
EMV Values
EMV (large plant)
EMV (small plant)
EMV (do nothing)
Point 1
Point 2
.167
.615
1
Values of P
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Using Excel
Program 3.1A
Input Data for the Thompson Lumber Problem Using Excel QM
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Using Excel
Program 3.1B
Output Results for the Thompson Lumber Problem Using Excel QM
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Decision Trees
- Any problem that can be presented in a decision table can also be graphically represented in a decision tree.
- Decision trees are most beneficial when a sequence of decisions must be made.
- All decision trees contain decision points or nodes, from which one of several alternatives may be chosen.
- All decision trees contain state-of-nature points or nodes, out of which 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
Figure 3.2
Favorable Market
Unfavorable Market
Favorable Market
Unfavorable Market
Do Nothing
Construct Large Plant
1
Construct Small Plant
2
A Decision Node
A State-of-Nature Node
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Thompson’s Decision Tree
Favorable Market
Unfavorable Market
Favorable Market
Unfavorable Market
Do Nothing
Construct Large Plant
1
Construct Small Plant
2
Figure 3.3
Alternative with best EMV is selected
EMV for Node 1 = $10,000
= (0.5)($200,000) + (0.5)(–$180,000)
EMV for Node 2 = $40,000
= (0.5)($100,000)
+ (0.5)(–$20,000)
Payoffs
$200,000
–$180,000
$100,000
–$20,000
$0
(0.5)
(0.5)
(0.5)
(0.5)
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Thompson’s Complex Decision Tree
Figure 3.4
First Decision Point
Second Decision Point
Favorable Market (0.78)
Unfavorable Market (0.22)
Favorable Market (0.78)
Unfavorable Market (0.22)
Favorable Market (0.27)
Unfavorable Market (0.73)
Favorable Market (0.27)
Unfavorable Market (0.73)
Favorable Market (0.50)
Unfavorable Market (0.50)
Favorable Market (0.50)
Unfavorable Market (0.50)
Large Plant
Small Plant
No Plant
6
7
Conduct Market Survey
Do Not Conduct Survey
Large Plant
Small Plant
No Plant
2
3
Large Plant
Small Plant
No Plant
4
5
1
Results
Favorable
Results
Negative
Survey (0.45)
Survey (0.55)
–$190,000
$190,000
$90,000
–$30,000
–$10,000
–$180,000
$200,000
$100,000
–$20,000
$0
–$190,000
$190,000
$90,000
–$30,000
–$10,000
Payoffs
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Thompson’s Complex Decision Tree
1. 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
2. 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
3. Compute the 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
4. If the market survey is not conducted,
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
5. The best choice is to seek marketing information.
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Thompson’s Complex Decision Tree
Figure 3.5
First Decision Point
Second Decision Point
Favorable Market (0.78)
Unfavorable Market (0.22)
Favorable Market (0.78)
Unfavorable Market (0.22)
Favorable Market (0.27)
Unfavorable Market (0.73)
Favorable Market (0.27)
Unfavorable Market (0.73)
Favorable Market (0.50)
Unfavorable Market (0.50)
Favorable Market (0.50)
Unfavorable Market (0.50)
Large Plant
Small Plant
No Plant
Large Plant
Small Plant
No Plant
Large Plant
Small Plant
No Plant
–$190,000
$190,000
$90,000
–$30,000
–$10,000
–$180,000
$200,000
$100,000
–$20,000
$0
–$190,000
$190,000
$90,000
–$30,000
–$10,000
Payoffs
Conduct Market Survey
Do Not Conduct Survey
Results
Favorable
Results
Negative
Survey (0.45)
Survey (0.55)
$40,000
$2,400
$106,400
$49,200
$106,400
$63,600
–$87,400
$2,400
$10,000
$40,000
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Expected Value of Sample Information
- Suppose Thompson wants to know the actual value of doing the survey.
= (EV with sample information + cost)
– (EV without sample information)
EVSI = ($49,200 + $10,000) – $40,000 = $19,200
Expected value
with sample
information, assuming
no cost to gather it
Expected value
of best decision
without sample
information
EVSI = –
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Sensitivity Analysis
- How sensitive are the decisions to changes in the probabilities?
- How sensitive is our decision to the probability of a favorable survey result?
- That is, if the probability of a favorable result (p = .45) where 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
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, $40,000
$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
- There are many ways of getting probability data. It can be based on:
- 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.
- It also allows the revision of initial estimates based on new information.
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Calculating Revised Probabilities
- In the Thompson Lumber case we used these four conditional probabilities:
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
- But how were these calculated?
- The prior probabilities of these markets are:
P (FM) = 0.50
P (UM) = 0.50
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Calculating Revised Probabilities
- Through discussions with experts Thompson has learned the information in the table below.
- He can use this information and Bayes’ theorem to calculate posterior probabilities.
Table 3.12
| STATE OF NATURE | ||
| RESULT OF SURVEY | FAVORABLE MARKET (FM) | UNFAVORABLE MARKET (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
- Recall Bayes’ theorem:
For this example, A will represent a favorable market and B will represent a positive survey.
where
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Calculating Revised Probabilities
- P (FM | survey positive)
- P (UM | survey positive)
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Calculating Revised Probabilities
Table 3.13
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 | X 0.50 | = | 0.35 | 0.35/0.45 = | 0.78 |
| UM | 0.20 | X 0.50 | = | 0.10 | 0.10/0.45 = | 0.22 |
| P(survey results positive) = | 0.45 | 1.00 |
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Calculating Revised Probabilities
- P (FM | survey negative)
- P (UM | survey negative)
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Calculating Revised Probabilities
Table 3.14
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 | X 0.50 | = | 0.15 | 0.15/0.55 = | 0.27 |
| UM | 0.80 | X 0.50 | = | 0.40 | 0.40/0.55 = | 0.73 |
| P(survey results positive) = | 0.55 | 1.00 |
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Using Excel
Program 3.2A
Formulas Used for Bayes’ Calculations in Excel
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Using Excel
Program 3.2B
Results of Bayes’ Calculations in Excel
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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
- 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
Figure 3.6
Your Decision Tree for the Lottery Ticket
Heads (0.5)
Tails (0.5)
$5,000,000
$0
Accept Offer
Reject Offer
$2,000,000
EMV = $2,500,000
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Utility Theory
- 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.
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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Standard Gamble for Utility Assessment
Figure 3.7
Best Outcome
Utility = 1
Worst Outcome
Utility = 0
Other Outcome
Utility = ?
(p)
(1 – p)
Alternative 1
Alternative 2
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Investment Example
- Jane Dickson wants to construct a utility curve revealing her 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, Jane would prefer to have her money in the bank.
- So if p = 0.80, Jane is indifferent between the bank or the real estate investment.
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Investment Example
Figure 3.8
Utility for $5,000 = U($5,000) = pU($10,000) + (1 – p)U($0)
= (0.8)(1) + (0.2)(0) = 0.8
p = 0.80
(1 – p) = 0.20
Invest in
Real Estate
Invest in Bank
$10,000
U($10,000) = 1.0
$0
U($0.00) = 0.0
$5,000
U($5,000) = p = 0.80
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Investment Example
Utility for $7,000 = 0.90
Utility for $3,000 = 0.50
- We can assess other utility values in the same way.
- For Jane these are:
- Using the three utilities for different dollar amounts, she can construct a utility curve.
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Utility Curve
Figure 3.9
U ($7,000) = 0.90
U ($5,000) = 0.80
U ($3,000) = 0.50
U ($0) = 0
1.0 –
0.9 –
0.8 –
0.7 –
0.6 –
0.5 –
0.4 –
0.3 –
0.2 –
0.1 –
| | | | | | | | | | |
$0 $1,000 $3,000 $5,000 $7,000 $10,000
Monetary Value
Utility
U ($10,000) = 1.0
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Utility Curve
- Jane’s utility curve is typical of a risk avoider.
- She gets less utility from greater risk.
- She avoids situations where high losses might occur.
- As monetary value increases, her 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.
- Someone with risk indifference will have a linear utility curve.
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Preferences for Risk
Figure 3.10
Monetary Outcome
Utility
Risk Avoider
Risk Indifference
Risk Seeker
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Utility as a
Decision-Making Criteria
- Once a utility curve has been developed it can be used in making decisions.
- This replaces monetary outcomes with utility values.
- The expected utility is computed instead of the EMV.
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Utility as a
Decision-Making Criteria
- Mark Simkin loves to gamble.
- He plays 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)?
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Utility as a
Decision-Making Criteria
Figure 3.11
Decision Facing Mark Simkin
Tack Lands Point Up (0.45)
Alternative 1
Mark Plays the Game
Alternative 2
$10,000
–$10,000
$0
Tack Lands
Point Down (0.55)
Mark Does Not Play the Game
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Utility as a
Decision-Making Criteria
- Step 1– Define Mark’s utilities.
U (–$10,000) = 0.05
U ($0) = 0.15
U ($10,000) = 0.30
- 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
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Utility Curve for Mark Simkin
Figure 3.12
1.00 –
0.75 –
0.50 –
0.30 –
0.25 –
0.15 –
0.05 –
0 –
| | | | |
–$20,000 –$10,000 $0 $10,000 $20,000
Monetary Outcome
Utility
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Utility as a
Decision-Making Criteria
Figure 3.13
Using Expected Utilities in Decision Making
Tack Lands Point Up (0.45)
Alternative 1
Mark Plays the Game
Alternative 2
0.30
0.05
0.15
Tack Lands
Point Down (0.55)
Don’t Play
Utility
E = 0.162
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
Copyright
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America.
Copyright ©2012 Pearson Education, Inc. publishing as Prentice Hall
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