380 likes | 595 Views
Decision Analysis. OPS 370. Decision Theory. A. B. a. b. c. d. e. Decision Theory. A. a. b. c. . Decision Theory. Steps: 1. A. B. 2. A. 3. 4. 5. Payoff Table. Shows Expected Payoffs for Various States of Nature. Decision Environments. A. a. B. a. C.
E N D
Decision Analysis OPS 370
Decision Theory • A. • B. • a. • b. • c. • d. • e.
Decision Theory • A. • a. • b. • c.
Decision Theory • Steps: • 1. • A. • B. • 2. • A. • 3. • 4. • 5.
Payoff Table • Shows Expected Payoffs for Various States of Nature
Decision Environments • A. • a. • B. • a. • C. • a.
Decision Making • A. • a. • b.
Decision Making • Under Uncertainty • Four Decision Criteria • 1. • A. • B. • 2. • A. • B.
Decision Making • Under Uncertainty • 3. • A. • B. • 4. • A. • B.
Example • Maximin • Indoor • Drive-In • Both • Choose “Best of Worst”
Example • Maximax • Indoor • Drive-In • Both • Choose “Best of Best”
Example • Laplace • Indoor • Drive-In • Both • Choose
Decision Making • Minimax Regret • Criterion for Decision Making Under Uncertainty • A. • B.
Decision Making • A. • Indoor • Drive-In • Both • B. • a.
Decision Making • Under Risk • A. • B. • a. • b.
Decision Making • Under Risk • Expected Payoffs: • Indoor: • Drive-In: (0.3)(700) + (0.5)(1500) + (0.2)(1250) = • Both: (0.3)(-2000) + (0.5)(-1000) + (0.2)(3000) = • Select
Expected Value of Perfect Info • A. • B.
Expected Value of Perfect Info • Steps: • 1. • 2. • 3. • Example • A. • a. • B. • C.
Expected Value of Perfect Info • NOTE: • A.
Decision Trees • Visual tool to represent a decision model • Squares: - Decisions • Circles: - Uncertain Events (Subject to Probability) • Branches: Potential Actions or Results • Some Branches are Terminal (End) Terminal Branches Have Payoffs (Payoffs Should Reflect All Costs/Revenues)
Decision Trees • Simple Example Terminal Branches $0 No $49 Buy Raffle Ticket? Win (0.01) Yes ($1 to Buy) Lose (0.99) -$1 Decision Uncertain Event
Decision Trees • Build Decision Trees from LEFT to RIGHT • Solve Decision Trees from RIGHT to LEFT • Determine Expected Values at Chance Nodes • Choose “Best” Expected Value at Decision Nodes • Identify “Best” Path of Decisions
Decision Trees • Simple Example $0 No $49 Buy Raffle Ticket? Win (0.01) Yes ($1 to Buy) Lose (0.99) -$1 Expected Value = (0.01)(49) + (0.99)(-1) = 0.49 – 0.99 = -0.5
Decision Trees • Simple Example • Should You Buy a Raffle Ticket? • NO! Your Expected Value is Negative $0 No Buy Raffle Ticket? Yes -$0.5
Decision Trees • More Complex Example
Decision Trees Settle Now ($?) Settle? Wait
Decision Trees Settle Now ($?) Opp Wins (0.5) Settle? Wait Opp Loses (0.5) $0
Decision Trees Settle Now ($?) Opp Sues (0.8) Opp Wins (0.5) Settle? No Suit(0.2) Wait Opp Loses (0.5) $0
Decision Trees Settle ($8) Settle Now ($?) Contest Opp Sues (0.8) Contest Settlement Opp Wins (0.5) Settle? No Suit(0.2) $0 Wait Opp Loses (0.5) $0
Decision Trees We Win (0.3) ($0) Settle ($8) Settle Now ($?) Contest Opp Sues (0.8) We Lose (0.7) ($10) Contest Settlement Opp Wins (0.5) Settle? No Suit(0.2) Low (0.4) ($5) $0 Wait Opp Loses (0.5) $0 Win (0.6) ($15)
Decision Trees We Win (0.3) ($0) Settle ($8) Settle Now ($?) Contest Opp Sues (0.8) We Lose (0.7) ($10) Contest Settlement EV = (0.3)(0) + (0.7)(10) = 7 Opp Wins (0.5) Settle? No Suit(0.2) Low (0.4) ($5) $0 Wait Opp Loses (0.5) $0 Win (0.6) ($15) EV = (0.4)(5) + (0.6)(15) = 11
Decision Trees Settle ($8) Settle Now ($?) Contest $7 Opp Sues (0.8) Contest Settlement Opp Wins (0.5) Settle? No Suit(0.2) $0 Wait $11 Opp Loses (0.5) $0
Decision Trees Settle Now ($?) $7 Opp Sues (0.8) Opp Wins (0.5) Settle? No Suit(0.2) $0 Wait Opp Loses (0.5) $0
Decision Trees Settle Now ($?) $7 Opp Sues (0.8) Opp Wins (0.5) Settle? No Suit(0.2) $0 EV = (0.8)(7) + (0.2)(0) = 5.6 Wait Opp Loses (0.5) $0
Decision Trees Settle Now ($?) $5.6 Opp Wins (0.5) Settle? Wait Opp Loses (0.5) $0
Decision Trees Settle Now ($?) $5.6 Settle? Opp Wins (0.5) Wait Opp Loses (0.5) $0 EV = (0.5)(5.6) + (0.5)(0) = 2.8
Decision Trees Settle Now ($?) Settle? $2.8 Wait