ECON6001/ECON6701 Microeconomics Analysis I Final Exam
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Final Exam , S2 2021,
ECON6001/ECON6701 Microeconomics Analysis I
Question 1. These questions involve only a quick calculation/response, sometimes using
the random values for some parameters displayed on the Canvas Quiz Portal. Solve them
and enter the solutions on the Canvas Quiz Portal.
1. Income distribution in a certain economy is given by a cumulative probability distrib- ution F. Suppose a policy is enacted such that the new distribution of income is given by G. Care was taken so that the mean income under both F and G are the same. Pick the correct choice to fill in the blanks and make the following a true statement:
G will Lorenz dominate F and result in A Average Poverty Index if and only if G B scholastically dominates F. In particular, we can conclude this since in this case C stochastic dominance implies D order stochastic dominance.
Fill in the blanks A, B, C and D choosing from the words such as lower, higher, equal, first order and second order . (Think carefully and write, there are no part
marks to this question.) (3 pts)
2. The profit of a certain firm producing a single output using inputs (x1 ; x2) at input prices (w1; w2) and output price p is given by
p(x1; x2 ; p ; w1; w2) = p x x ¡ w1x1 ¡ w2x2 :
Suppose that at a given (p ; w ; w), you are told that the profit maximizing choice is (x ; x) = (a ; b). Now suppose there is an infinitesimal change in w1 . Use the appropriate theorem to derive the change in optimal profit . Denote the expression you get by A.
For the random values of a and b on the Canvas, enter the value of A. (3 pts)
3. Which of the following statements are true? Throughout X = fx1; x2g are the two possible outcomes and p = (p1 ; p2); q = (q1; q2) etc. denote lotteries.
a. Suppose x1 ⃞ x2 . Under EUH, we may normalize the utility representation so that p ⃞ q if and only if p1 > q1 .
b. U(p) = x1 x2 and W(p) = p1log(x1) + p2 log(x2) represent the same preference relation on lotteries where p2= 1 + p1 .
c. U(p) = p1 log(x1) + p2 x2 is consistent with the Expected Utility Hypothesis.
d. Part (c). Moreover, U(p) in Part (c) and W(p) = p1 log(x1)+ p2 log(x2) represent the same preferences, since log(x2) is a positive monotone transform of x2 .
Enter a, b, c, or d on Canvas Quiz in the space provided. You can also enter a,b
for example if you think that both a and b are correct. (3 pts)
4. Suppose the vNM utility function for money outcomes of a certain consumer is given by v(x) = a + b x + c x2 for all x > 0, where a ; b and c are some parameters. For the consumer to be strictly risk averse, the restrictions on the parameters a ; b ; c are:
a is A , b is B and c is C .
Fill in the blanks A, B and C with words such as unrestricted, positive, negative,
non-negative, non-positive . (3 pts)
5. There are three outcomes f` ; m ; hg in an environment where EUH is satisfied. The vNM utilities are v` = 0, vh = 1 and vm 2 (0; 1). The right angled triangle with the thick outline shows the set of all possible lotteries.
Figure 1.
Derive the slope of a typical indifference curve. Then on Canvas fill in the blank
broken line in the above figure depicts a typical indifference curve. (3 pts)
Question 2 There are three statements. You are required to comment on each of those
statements. Answer in few sentences. You may even present your argument as a list of bullet points or make your point with a simple picture/example/counter example.
Anything written over half an A4 page will be ignored.
1. In the context of bargaining theory studied in class, having an outside option and being the first mover necessarily
2. By the Folk Theorem for Repeated Games every payoff combination in the convex hull of payoffs can be supported as a SPE outcome. Therefore the theory has no predictive content. (5 pts)
3. Since the VCG mechanism admits a dominant strategy equilibrium, the means infor- mational constraints are irrelevant, one can always achieve ex-post efficient outcomes in bilateral trade. Comment. (5 pts)
Question 3. The game in the table below, denoted by G, describes payoffs
from a certain Cournot duopoly in which two firms can choose quantities qm < qc < qh . By way of interpretation, qm stands for the output that the firms would have chosen jointly as a monopoly, qc the Cournot equilibrium output if they were to play a one-shot game and qh some other output.
qm qc qh
qm qc qh
36; 18 |
30; 20 |
27; 20.25 |
40; 15 |
32; 16 |
28; 15.75 |
40.5; 13.5 |
31.5; 14 |
27; 13.5 |
Table 1. One shot game G.
Now consider the game G1(), i.e. the infinite repetition of G with discount factor .
1. Consider supporting the monopoly price as an equilibrium using a Grim-trigger strategy in this game: Play qm to begin with and continue to play qm unless some player has played some other action, in which case switch to qh. What is the minimum value of such that this strategy profile constitutes a sub-game perfect equilib- rium of this game. (5 pts)
2. Consider now the case when both players are restricted to play only qm or qc. Now consider the new Grim-trigger strategy: Play qm to begin with and continue to play qm unless some player has played some other action, in which case switch to qc . Find the values of for which both players playing this strategy profile is an equilibrium.(5 pts)
3. Bearing in mind that qm < qc < qh and using your answers to the two previous parts, comment (two or three sentences) on excess capacity as a device for sustaining implicit collusion. (5 pts)
Question 4 Consider allocating an object to one of two players when each player's pref-
erences are her private information. Player 1's value for the object, denoted by v1 is drawn from a continuous distribution with [1; 2] as its support. Player 2's value for the object, denoted by v2, is likewise drawn from the interval [0; 1].
1. What is the equilibrium in dominant strategies if a second price auction is used to allocate the object. Is the outcome ex-post efficient? (3 pts)
2. For what pairs (v1; v2) should Player 1 and Player 2 respectively be allocated the object in a mechanism that maximizes expected revenue for the seller? (4 pts)
3. Comment on the differing allocations you obtained in the previous two parts. (3 pts)
2021-12-14