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U8216 Microeconomics and Policy Analysis Fall 2000 Problem Set 5 1.
The date is January 1, 2000. A zero coupon bond is a bond
that pays out nothing until it comes due and then it pays out its face
value. Suppose that a zero coupon bond with a $1,000 face value
becomes due on January 1, 2015. Given an unchanging interest rate of
15%, what will this bond sell for today? 2.
Assume the interest rate is 10%. A plot of land can be used
in one of two ways. Option 1 is to use the land for a parking lot.
There are no startup costs in building the lot, and it yields a net return
of $8,000 per year forever starting next year. Option 2 is to build
a house, at a cost of $50,000 now with a net return of $12,000 a year
forever (also starting next year). a.
How should the land be used? Is the answer the same if the
interest rate goes down to 5%? Explain. b.
Does your answer to (a) change if, instead of a net return of
$12,000 forever on the house, you get a return of $12,000 today and a net
return of $12,000 for 30 years (starting in 1 year)? 3.
Suppose you are 30 and have just graduated with your MPA. You
plan to work for exactly 30 years, retire for 20 years, and then drop
dead. Suppose your salary from today till retirement is constant in real
terms (i.e. inflation-adjusted). You wish to retire with an annual
income that is 60% of your salary. Today a government bond pays a
real return of about 2% annually (the market rate is about 5%, but the
inflation rate is about 3%). Suppose the rate will be constant forever (in
fact, real rates display little variation in most circumstances). a.
Figure out how much money as a fraction of your salary you will
need to save in order to meet your retirement goals? (Hint: figure
everything out in terms of present values today.) b.
Suppose you save 15% of your salary. How many years of
retirement will your savings fund? (Hint: solve for an unknown N,
where N is the number of years of retirement. You will need to use
logarithms.) c.
The US Social Security system is funded by contributions of about
15% of salary (up to a limit, but benefits are also limited so you can
ignore this complication). The interest rate and benefit levels are
close to those assumed above. Should Clinton start a campaign to
encourage old people to start smoking? Suppose we let people invest
their contributions in private sector securities that pay higher rates but
are just as safe for long-term investments. Why would this strategy
help the situation (suppose that the returns on government securities and
private sector securities is not changed by the policy)? If the
government is buying these securities, who will not be buying them?
Does this matter? 4.
Winfred Whiz is playing on a game show. He must choose
between two offers. The first offer is a payment of $2,000, which he
can take for simply being on the show, or he can enter a gamble. In
the gamble, he chooses one of two curtains that conceal two items.
He makes a draw for curtain 1 or 2 from a hat and then receives the gift
behind the curtain picked. He knows that behind one curtain is an
automobile valued at $4,000 and behind the other curtain is a set of
encyclopedias valued at $500. If his initial wealth is $1,000 and
his utility function can be described by: U(w) = 1 –
then what must be the probability of drawing the car
for Winfred to be indifferent between the two choices? 5.
Betty Bat loves the New York Yankees. She has followed their
exploits since she was five years old. In three of the past four
years (1996, 1998, 1999) they won the World Series, and Betty thinks they
can do it again next year. Betty has just thought up a clever plan.
She has $1,000 of savings that she has hidden under her bed. She
could spend $600 of the $1,000 in making Yankees championship
paraphernalia: buttons, cups, pens, and so on. Then, if the Yankees
win, she estimates that she would earn $1,500. If the Yankees lose,
she won’t be able to sell any of her stock. Betty figures that the
Yankees have a 0.6 chance of winning the next World Series.
Betty’s utility function is given by: U(w) =
a.
If Betty is an expected utility maximizer, will she make the $600
investment into Yankee championship gadgets? b.
Calculate the certainty equivalent of Betty’s clever prospect. c.
Suppose that a friend offers her insurance. He says to Betty,
"If you pay me F dollars whether or not the Yankees win, then,
in the event that the Yankees lose, I will pay you $1,500, the amount that
you would have earned had the Yankees won the World series. If the
Yankees win, I will pay you nothing." What is the maximum value
of F that Betty is willing to pay for the insurance policy?
If Betty’s friend is risk-neutral, will he gain by this venture?
Explain. d. If Betty purchases the insurance on the $600 investment, might a moral hazard problem arise in which Betty shirks on her efforts to sell the Yankee merchandise? Why or why not? 6.
Jack has a house worth $100. There
is a 5% chance that his house will catch a fire that will cause $64 of
damage. Jill has $100 cash
and is willing to offer Jack some form of insurance scheme as follows:
Jack pays Jill a premium a.
If there is no fire, Jill keeps the premium.
If the house catches fire, Jill will refund a
and pay for the fire damages. If
their utility functions of wealth is given by: UJack
(M) =
UJill
(M) =
(a)
What is the maximum premium that Jack is willing to pay? (b)
What is the minimum premium that Jill is willing to accept? (c)
Can they reach a deal? 7.
(optional) Ms
Gamble currently has an income of $25,000. Assign the utility number
100 to this income level and the utility number 85 to the income level
$20,000. It is known that Ms Gamble would be willing to pay a
maximum of $5,000 for a lottery ticket that yields $10,000 with a
probability of
8.
(optional) Suppose
now that using the lot for the house costs the same and yields the same
return as in the previous question, 2b (let the interest rate be 10%).
The parking lot, if successful, now yields $16,000 forever with
probability 0.5, or nothing forever with probability 0.5. Suppose
your utility function of wealth is given by U(I) =
a.
Compute the expected return of investing in the parking lot. b.
Which option will you pursue now? Compare your answer to that
of problem 2b and justify your answer. c.
Suppose you may now try out the land as a parking lot for 1 year.
If successful, you will always use the lot as a parking lot. If a
flop, you will build the house next year with the return and cost
specified as before. Compute the present value of each possible
outcome. Which option will you pursue now? Explain. 9.
(optional) Given
a venture with a 50-50 chance of succeeding, and a utility function of U=
10.
(optional) After
making a $100,000 killing in cattle futures, you are considering investing
your winnings in a portfolio of two alternative investments. The
first is a risk-free bond that pays 10% always. The second is a
stock that has a 0.4 probability of paying 15%, a 0.3 probability of
paying 18%, and a 0.3 chance of paying a 6% return. a.
Find the expected return, variance, and standard deviation of the
stock. b.
Show graphically the risk-return combinations of the different
portfolios that you could buy (i.e. the budget line between expected
return and risk as measured by the standard deviation of the portfolio).
What is the slope of the budget line? Interpret the meaning of the
slope. c.
Suppose that you decide to invest $70,000 in the stock and $30,000
in the bond. What is the expected return and standard deviation of
the portfolio you have chosen?
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