Unit 8: Game Theory - Practice Quiz

DEECO515 60 Questions
0 Correct 0 Wrong 60 Left
0/60

1 In game theory, a game is best defined as a situation involving:

meaning and types of games Easy
A. A single decision-maker choosing in isolation with no external influence
B. Strategic interaction where the outcome for each player depends on the actions of all players
C. A random process with no rational participants
D. A market with perfect competition and no rivalry

2 The individuals or firms who make decisions in a game are called:

meaning and types of games Easy
A. Strategies
B. Payoffs
C. Players
D. Outcomes

3 A game in which the total gains of the players exactly equal the total losses is called a:

meaning and types of games Easy
A. Zero-sum game
B. Repeated game
C. Positive-sum game
D. Cooperative game

4 A game in which players can form binding agreements and coordinate their strategies is known as a:

meaning and types of games Easy
A. Non-cooperative game
B. Cooperative game
C. Zero-sum game
D. Sequential game

5 A game in which players move one after another rather than at the same time is called a:

meaning and types of games Easy
A. Simultaneous game
B. Symmetric game
C. Sequential game
D. Constant-sum game

6 The numerical rewards that players receive from the various combinations of strategies are called:

meaning and types of games Easy
A. Players
B. Payoffs
C. Rules
D. Moves

7 A dominant strategy is one that:

dominant strategy and Nash equilibrium Easy
A. Is always the strategy with the lowest possible cost
B. Yields the highest payoff for a player regardless of what the other players do
C. Is chosen randomly among all available strategies
D. Gives a player the best payoff only if the rival cooperates

8 A Nash equilibrium occurs when:

dominant strategy and Nash equilibrium Easy
A. All players choose to cooperate fully
B. No player can improve their payoff by unilaterally changing their own strategy
C. The total payoff of the game is maximized
D. Every player earns exactly the same payoff

9 The concept of Nash equilibrium is named after:

dominant strategy and Nash equilibrium Easy
A. Adam Smith
B. Oskar Morgenstern
C. John Nash
D. John von Neumann

10 If every player in a game plays their dominant strategy, the resulting outcome is called a:

dominant strategy and Nash equilibrium Easy
A. Dominant strategy equilibrium
B. Cooperative solution
C. Random equilibrium
D. Mixed strategy outcome

11 Which statement about dominant strategies and Nash equilibrium is correct?

dominant strategy and Nash equilibrium Easy
A. Nash equilibrium only exists in cooperative games
B. A game can never have a Nash equilibrium without dominant strategies
C. Every Nash equilibrium requires dominant strategies
D. A dominant strategy equilibrium is also a Nash equilibrium

12 A strategy that always gives a lower payoff than another available strategy, regardless of rivals' choices, is called a:

dominant strategy and Nash equilibrium Easy
A. Dominant strategy
B. Dominated strategy
C. Maximin strategy
D. Mixed strategy

13 The prisoner's dilemma illustrates a situation where:

prisoner's dilemma Easy
A. Players can communicate and coordinate perfectly
B. Both players always choose to cooperate
C. Individually rational choices lead to a collectively worse outcome
D. There is no possible equilibrium in the game

14 In the classic prisoner's dilemma, the dominant strategy for each prisoner is to:

prisoner's dilemma Easy
A. Confess (defect)
B. Randomize between confessing and staying silent
C. Stay silent (cooperate)
D. Wait for the other prisoner to decide first

15 In the prisoner's dilemma, the outcome where both players cooperate is:

prisoner's dilemma Easy
A. A dominant strategy equilibrium
B. Always the Nash equilibrium of the game
C. Impossible to describe using payoffs
D. Better for both players than the Nash equilibrium, but not stable

16 The prisoner's dilemma is often used in economics to explain the behavior of firms in:

prisoner's dilemma Easy
A. A monopoly with a single seller
B. An oligopoly deciding whether to collude or compete
C. A perfectly competitive market
D. A market with no strategic interaction at all

17 In the prisoner's dilemma, "defecting" refers to a player choosing to:

prisoner's dilemma Easy
A. Cooperate with the other player
B. Leave the game entirely
C. Split the payoff equally
D. Pursue self-interest at the expense of joint benefit

18 A mixed strategy is one in which a player:

mixed strategy Easy
A. Assigns probabilities to two or more possible strategies
B. Always chooses the same single action
C. Never participates in the game
D. Copies exactly what the opponent does

19 A strategy in which a player always selects one particular action with certainty is called a:

mixed strategy Easy
A. Mixed strategy
B. Dominated strategy
C. Pure strategy
D. Random strategy

20 If a player uses a mixed strategy playing action A with probability , then the probability of playing the only other action B is:

mixed strategy Easy
A.
B.
C.
D.

21 In a simultaneous-move game, players choose their strategies:

meaning and types of games Medium
A. Only when a dominant strategy exists
B. After observing every rival's action
C. In a fixed order set by the referee
D. Without knowing the choices of the other players

22 A game in which one player's gain is exactly equal to the other player's loss is called a:

meaning and types of games Medium
A. Positive-sum game
B. Zero-sum game
C. Cooperative game
D. Repeated game

23 Which feature best distinguishes a cooperative game from a non-cooperative game?

meaning and types of games Medium
A. Players always earn equal payoffs
B. Players can form binding, enforceable agreements
C. No player has a dominant strategy
D. The game is always played only once

24 A game that is played more than once by the same players, allowing strategies to depend on past behaviour, is known as a:

meaning and types of games Medium
A. Repeated game
B. Static game
C. One-shot game
D. Constant-sum game

25 A strategy is a dominant strategy for a player if it:

dominant strategy and Nash equilibrium Medium
A. Equalizes payoffs across all players
B. Is best only when rivals cooperate
C. Maximizes the sum of all players' payoffs
D. Yields the highest payoff regardless of what rivals do

26 At a Nash equilibrium, each player's chosen strategy is:

dominant strategy and Nash equilibrium Medium
A. The strategy that maximizes joint welfare
B. Guaranteed to be a dominant strategy
C. Chosen randomly with equal probability
D. A best response to the strategies of the other players

27 Consider a game. Firm A's payoffs from High are and from Low are against Firm B's Left, Right. If Firm B's payoffs make Left dominant for B, which strategy will Firm A rationally anticipate B playing?

dominant strategy and Nash equilibrium Medium
A. Left
B. Right
C. A mix of Left and Right
D. Neither, since A also needs a dominant strategy

28 Which statement about the relationship between dominant strategies and Nash equilibrium is correct?

dominant strategy and Nash equilibrium Medium
A. A Nash equilibrium is always a dominant-strategy equilibrium
B. A dominant-strategy equilibrium is always a Nash equilibrium
C. Nash equilibrium requires no dominant strategy to exist
D. The two concepts are unrelated

29 In a game, deleting a player's strictly dominated strategy is justified because:

dominant strategy and Nash equilibrium Medium
A. It always increases the deleting player's payoff to zero
B. It converts the game into a zero-sum game
C. A rational player would never play a strictly dominated strategy
D. It guarantees a unique Nash equilibrium

30 A game has payoff cells where both players' payoffs, listed as (Row, Column), are: TL , TR , BL , BR . Which cell is the Nash equilibrium?

dominant strategy and Nash equilibrium Medium
A. TL
B. BL
C. TR
D. BR

31 The central paradox of the prisoner's dilemma is that:

prisoner's dilemma Medium
A. Individually rational choices lead to a jointly worse outcome
B. Cooperation is always the dominant strategy
C. No Nash equilibrium exists in the game
D. Both players are guaranteed their best payoff

32 In the classic prisoner's dilemma, the Nash equilibrium outcome is:

prisoner's dilemma Medium
A. One cooperates while the other defects
B. Players randomize equally between choices
C. Both players defect (confess)
D. Both players cooperate (stay silent)

33 Two firms in a duopoly face a prisoner's-dilemma pricing situation. Why do they often end up in a price war despite both preferring high prices?

prisoner's dilemma Medium
A. Neither firm has a Nash equilibrium
B. Consumers force both firms to lower prices
C. High prices always violate antitrust law
D. Cutting price is a dominant strategy for each firm individually

34 In an infinitely repeated prisoner's dilemma, cooperation can be sustained mainly because:

prisoner's dilemma Medium
A. Defection stops being a feasible strategy
B. Players lose the ability to observe past actions
C. The game becomes zero-sum
D. Future punishment for defection can outweigh the short-term gain

35 Which real-world scenario is best modelled as a prisoner's dilemma?

prisoner's dilemma Medium
A. A monopolist setting price with no rivals
B. Two firms deciding whether to honour or break a cartel output agreement
C. A consumer selecting between two brands of soap
D. A single firm choosing its profit-maximizing output

36 A mixed strategy is one in which a player:

mixed strategy Medium
A. Copies the rival's previous move exactly
B. Chooses the strategy with the highest guaranteed payoff
C. Randomizes over pure strategies according to a probability distribution
D. Always plays the same single action

37 In a mixed-strategy Nash equilibrium, each player chooses probabilities that make the opponent:

mixed strategy Medium
A. Indifferent between their own pure strategies
B. Unable to compute a best response
C. Certain to play a dominant strategy
D. Worse off than in any pure strategy

38 In Matching Pennies, Player A wants to match and Player B wants to mismatch. The mixed-strategy Nash equilibrium has each player choosing Heads with probability:

mixed strategy Medium
A.
B.
C.
D.

39 Suppose Player 2 plays Left with probability . Player 1's payoff from Up is and from Down is . For which is Player 1 indifferent between Up and Down?

mixed strategy Medium
A.
B.
C.
D.

40 According to Nash's existence theorem, every finite game with a finite number of players and strategies has:

mixed strategy Medium
A. A dominant strategy for every player
B. No equilibrium unless it is zero-sum
C. Exactly one pure-strategy Nash equilibrium
D. At least one Nash equilibrium, possibly in mixed strategies

41 Consider a game where Player 1's payoffs (Player 1, Player 2) are: , , , . Player 2 chooses columns or . Which statement is correct?

dominant strategy and Nash equilibrium Hard
A. Player 1 has a dominant strategy and the unique Nash equilibrium is
B. Neither player has a dominant strategy but is a Nash equilibrium
C. Player 2 has a dominant strategy and the equilibrium is
D. Player 1 has a dominant strategy and the unique Nash equilibrium is

42 In matching pennies, Player 1 wins when the coins match and loses otherwise; Player 2 has opposite payoffs. If Player 2 plays Heads with probability , for what is Player 1 indifferent between Heads and Tails?

mixed strategy Hard
A.
B.
C.
D.

43 A game qualifies as a prisoner's dilemma with actions Cooperate (C) and Defect (D) and payoffs ordered by the temptation , reward , punishment , and sucker . Which condition set is necessary and sufficient?

prisoner's dilemma Hard
A. and
B. and
C. and
D. and

44 Which statement about the relationship between dominant-strategy equilibria and Nash equilibria is correct?

dominant strategy and Nash equilibrium Hard
A. The two concepts are always equivalent in finite games
B. A dominant-strategy equilibrium may fail to be a Nash equilibrium in mixed strategies
C. Every dominant-strategy equilibrium is a Nash equilibrium, but not every Nash equilibrium is a dominant-strategy equilibrium
D. Every Nash equilibrium is a dominant-strategy equilibrium, but not conversely

45 In the Battle of the Sexes, payoffs are: both choose Opera , both choose Football , and mismatches . In the mixed-strategy Nash equilibrium, what probability does the row player (payoff 2 at Opera) assign to Opera?

mixed strategy Hard
A.
B.
C.
D.

46 A game is described as one where the sum of all players' payoffs is a fixed constant regardless of the outcome, and players move without observing each other's choices. This game is best classified as:

meaning and types of games Hard
A. Zero-sum and sequential-move
B. Constant-sum and simultaneous-move
C. Positive-sum and cooperative
D. Non-constant-sum and simultaneous-move

47 In a game solved by iterated elimination of strictly dominated strategies (IESDS), which property holds?

dominant strategy and Nash equilibrium Hard
A. The order of elimination does not affect the final surviving set of strategies
B. The order of elimination can change the surviving set for strict dominance
C. Strategies eliminated by IESDS may still appear in a Nash equilibrium
D. IESDS always leaves exactly one strategy per player

48 In an infinitely repeated prisoner's dilemma with discount factor , players use grim-trigger strategies to sustain cooperation. With , , , , what is the minimum for cooperation to be sustainable?

prisoner's dilemma Hard
A.
B.
C.
D.

49 Nash's theorem guarantees that every finite game has at least one equilibrium. Which precise statement captures this result?

mixed strategy Hard
A. Every finite strategic game has at least one Nash equilibrium in pure strategies
B. Every finite game has a unique mixed-strategy equilibrium
C. Every finite game has a dominant-strategy equilibrium in mixed strategies
D. Every finite strategic game has at least one Nash equilibrium in mixed strategies

50 Consider Cournot duopoly with inverse demand , , and zero marginal cost. The Nash equilibrium output per firm is:

dominant strategy and Nash equilibrium Hard
A.
B.
C.
D.

51 Why is the prisoner's dilemma outcome (mutual defection) described as Pareto-inefficient?

prisoner's dilemma Hard
A. One player is always strictly worse off than in any other outcome
B. It is not a Nash equilibrium of the game
C. Both players could be made better off by mutual cooperation without harming anyone
D. It maximizes the joint payoff but not individual payoffs

52 Consider a zero-sum game with row player payoff matrix (rows = row's strategies, columns = column's). What is the value of the game?

mixed strategy Hard
A.
B.
C.
D.

53 A game has perfect information if and only if:

meaning and types of games Hard
A. Every information set is a singleton, so each player observes all prior moves
B. No player has private information about payoffs
C. All players share the same payoff function
D. The game is played only once with simultaneous moves

54 In a three-strategy symmetric game, strategy is strictly dominated by a mix of and but is not dominated by any pure strategy. What can we conclude?

dominant strategy and Nash equilibrium Hard
A. cannot be eliminated because no pure strategy dominates it
B. is a dominant strategy in the reduced game
C. can be eliminated by IESDS only if mixed strategies are allowed in the domination test
D. is part of every Nash equilibrium

55 In a finitely repeated prisoner's dilemma played exactly times with fully rational players and common knowledge of rationality, what is the subgame-perfect equilibrium?

prisoner's dilemma Hard
A. Cooperate in every period if is large
B. Cooperate until the last period, then defect
C. Defect in every period, by backward induction
D. Alternate cooperate and defect each period

56 A key principle of mixed-strategy equilibria is that a player randomizes only when indifferent. What determines each player's equilibrium mixing probabilities?

mixed strategy Hard
A. The opponent's payoffs, which the player's mix must make indifferent
B. The average of both players' payoffs
C. The player's own payoffs, which set their own indifference
D. The player's risk aversion toward high payoffs

57 Which distinction correctly separates cooperative from non-cooperative game theory?

meaning and types of games Hard
A. Cooperative theory ignores individual payoffs entirely
B. Cooperative theory allows binding, enforceable agreements; non-cooperative theory does not
C. Non-cooperative theory forbids any communication between players
D. Cooperative theory studies only positive-sum games; non-cooperative studies zero-sum games

58 Two firms simultaneously choose price High or Low. Payoffs (Firm1, Firm2): , , , . Identify the Nash equilibrium.

dominant strategy and Nash equilibrium Hard
A. with payoffs
B. with payoffs
C. with payoffs
D. Both and are equilibria

59 A rock-paper-scissors game with symmetric win/loss/tie payoffs of has which equilibrium?

mixed strategy Hard
A. Three pure equilibria, one per action pair
B. A mixed equilibrium with probabilities
C. No equilibrium exists because it is a cyclic game
D. A unique mixed equilibrium where each action is played with probability

60 In a one-shot prisoner's dilemma, adding a small communication (cheap-talk) stage before players choose actions will:

prisoner's dilemma Hard
A. Convert defection into a dominated strategy
B. Guarantee mutual cooperation once players promise it
C. Not change the equilibrium, since promises to cooperate are not credible
D. Create a new dominant strategy of cooperation