Temple University
Department of Economics

Economics 92
Principles of Microeconomics, Honors

Homework 6
Mixed Strategies


A. Market Niche is important to any firm since it confirms a certain degree of market power and pricing discretion.  This is a problem about entry and market niche; and it is a first problem in mixed strategy.

There is a new market in intelligent human-like robots, but there is room for only one firm.  Miss Anne Thrope and Andy Royd own firms that could manufacture the new robots.  If only one firm enters then it earns profits of $100. If they both enter then each of them loses $50.  If neither of them enters then no one earns a profit.  The payoffs can be summarized as
  Andy Royd
Enter Stay Out
Miss Anne Thrope Enter -50, -50 100, 0
Stay Out 0, 100 0, 0

1. Does Miss Anne Thrope have a dominant strategy?

2. Does Andy Royd have a dominant strategy?

3. Using "best response", how many pure strategy equilibria are there?

4. With what probability should Andy Royd play "Enter?"

5. With what probability should Miss Anne Thrope play "Stay Out?"

6. What is the expected payoff to Andy Royd from playing the mixed strategy?

7. What percent of the time will too many firms enter the robot market?

8. In the sense of maximizing total payoff to all players, is the mixed strategy solution that you have found an efficient outcome? Yes  No

9. In the sense that on average each player does as well as the other, is the mixed strategy solution fair? Yes  No

10. Is there a way to reconcile fairness and efficiency? Yes  No


B. Video System Coordination (VHS v. Beta) was a problem when VCR's were first introduced.  A similar problem emerged with DVD and high density TV so it is worth looking closely at coordination games and mixed strategies.  Sony and Panasonic can choose from either of two formats, VHS or Beta.  If they use the same format then they are better off.  If they use different formats then no one is better off.  They payoffs can be summarized as

Beta VHS
Panasonic Beta 1, 1 0, 0
VHS 0, 0 1, 1

11. There are two pure strategy equilibria in this game.  What are they?

Equilibrium  Panasonic's strategy Sony's startegy

12. Are the pure strategy solutions fair in the sense of equal payoffs? Yes  No

13. Are the pure strategy solutions efficient? Yes  No

14. With what probability should Sony play Beta in a mixed strategy?

15. What is Sony's expected payoff in the mixed strategy solution?

16. Is the mixed strategy solution to the game fair in the sense of both players getting the same payoff? Yes  No

17. Is the mixed strategy solution to the game efficient in the sense of maximizing the total payoff for all players? Yes  No


C. Sales are foremost in our minds now that the Christmas shopping season is behind us.  With expansion of retail outlets and the poor results of the season Anna Conda, the VP for Sales and Marketing, must decide on a new strategy: Periodic sales or 'everyday low prices.'  When Conda's firm has a sale they pick up new informed buyers who were waiting for a price drop, as well as winning customers from their rival.  If both firms have a sale the Anna is worse off.  If Anna holds her price when Turnitif has a sale then she will pick up some customers who want her trademark.  Anna Conda's research assistant has determined that payoffs in their retail market are

  Anna Conda
Normal Price Sale Price
Al Turnitif Normal Price 175, 100 100, 200
Sale Price 150, 150 120, 90

18. Does Conda have a dominant strategy? Yes   No

19. Does Turnitif have a dominant strategy? Yes   No

20. Is there an equilibrium in pure strategies? Yes   No

21. If Anna Conda starts a new campaign in which she promises sale prices all of the time what will be her profits?

22. Is there a mixed strategy equilibrium? If your answer is yes then fill in the blanks:

Player Probability to play
 Normal Price
Probability to play
 Sale Price
Al Turnitif
Anna Conda