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Optimal mixed strategy

Prerequisites to find the optimal mixed strategy

Section titled “Prerequisites to find the optimal mixed strategy”
  1. Check for and eliminate dominated strategies and remove them.
  2. Check for a stable solution (if max row min = min column max).
  3. If no stable solution, find the optimal mixed strategy:
  • Let player 1’s option be played with probability .
  • This means player 1’s option will be played with probability
  • Create an expression for each of player 2’s options.
  • Find the point(s) where all the expressions are equal.
  • Of these points, find the one where the lowest lines at that value of are the highest they can be.
  • Solve these two lines simultaneously to find .

Find the probabilities for a mixed strategy fro player 1, assuming player 2 plays randomly

Section titled “Find the probabilities for a mixed strategy fro player 1, assuming player 2 plays randomly”
Player 2 plays DPlayer 2 plays E
Player 1 plays A12
Player 1 plays C3-1
  • player 2 plays randomly between D and E.
  • Let player 1 play A with probability .
  • They therefore play C with probability .
  • If player 2 plays D, player 1 wins .
  • If player 2 plays E, player 1 wins .
  • Solve simultaneously:
    • .
  • Answer: player 1 should play A with probability and C with probability . .

Remember that player 1 must play these strategies as randomly as possible. That’s because they don’t want player 2 to be able to predict what they will do.

Find the probabilities for a mixed strategy for player 1, assuming player 1 plays randomly (2xn)

Section titled “Find the probabilities for a mixed strategy for player 1, assuming player 1 plays randomly (2xn)”
Player 2 plays CPlayer 2 plays DPlayer 2 plays E
Player 1 plays A0-12
Player 1 plays B23-2

Add the row minima and column maxima:

Player 2 plays CPlayer 2 plays DPlayer 2 plays ERow minima
Player 1 plays A0-12-1
Player 1 plays B23-2-2
Column maxima232
  • Let player 1 play A with probability .
  • They therefore play B with probability .
  • If player 2 plays C, player 1 wins .
  • If player 2 plays D, player 1 wins .
  • If player 2 plays E, player 1 wins .
  • Drawing the graph, the point where all the lines are the highest is at the intersection of and .
  • Solve simultaneously:
    • .
  • Answer: they should play A with probability and B with probability . .