SERVER
Forehand Backhand
Forehand 90,1 0,10
RECEIVER
Backhand 0,10 6,4
The idea in this game is to see what happens to Game 1 when one payoff- (9,1)-- is drastically changed-- to (90,1). It's not tennis anymore, but let's see what happens.
2_2 What is the Nash equilibrium probability of Forehand for the Receiver?
A. Between 0 and .2, inclusive.
B. Greater than .2 but less than .5.
C. Between .5 and .7, inclusive
D. Greater than .7
D. Try again. If the Receiver chooses such a high probability of Forehand, the Server can take advantage of that by serving to his Backhand all the time.
If the Receiver chooses the a probability of .8, for example, then
Server's Payoff (Forehand) = .8 (1) + .2(10) = 2.8 < Server's Payoff (Backhand) =.8(10) + .2 (4) =8.8,
so the Server will serve to his Backhand all the time.
To get the correct answer, you need to choose a mixing probability Y for the Receiver such that the Server does no better from Forehand than from Backhand. To do that, you solve
Server's Payoff (Forehand) = Y (1) + (1-Y)(10) = Server's Payoff (Backhand) =Y(10) + (1-Y)(4).
Return to Self Test 2.