ECN130 Economic Analysis and Policy Answers
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ECN130
DEPARTMENT OF ECONOMICS
Economic Analysis and Policy
Specimen Exam
SECTION A
1. Dan collects data reflecting the market for Henderson’s Relish in Sheffield. He finds that when the price is £4.00 per bottle, 7000 bottles are sold. When the price is £3.50 per bottle, 9000 bottles are sold. Based on this information, the price elasticity of demand for Henderson’s Relish is:
A. -0.533
B. -1.875
C. -1.530
D. -0.833
2. Students in Sheffield can travel to Manchester by bus or train. A decrease in the price of train tickets causes the:
A. demand curve for bus tickets to shift left, and the demand curve for train tickets to shift left.
B. demand curve for bus tickets to shift left, and the quantity demanded for
train tickets to increase.
C. quantity demanded for bus tickets to fall, and the demand curve for train
tickets to shift left.
D. demand curve for bus tickets to shift right, and quantity demanded for train tickets to increase.
3. Jesse consumes coffee every day. His preferences for coffee conform to the principle of diminishing marginal utility. Given this, which of the following CANNOT be true:
A. Jesse’s total utility will decrease if he drinks more than five cups of coffee in a day.
B. Jesse’s total utility is 5 utils from one cup of coffee, 11 utils from two cups
of coffee and 18 utils from three cups of coffee.
C. Jesse receives 4 utils from his second cup of coffee and 2 utils from his fourth cup of coffee.
D. Jesse’s total utility is 5 utils from one cup of coffee and 12 utils from four cups of coffee.
4. Steven’s preferences satisfy non-satiation. He prefers pizza to hotdogs, and he prefers hotdogs to hamburgers. Based only on this information, which of the following is definitely true?
A. Steven prefers 3 hamburgers to 1 hotdog.
B. Steven prefers pizza to hamburgers.
C. Steven prefers 3 hamburgers and 1 hotdog to 2 hamburgers and 1
hotdog.
D. For any two combinations of a quantity of hotdogs and a quantity of pizza, Steven can tell you which he prefers.
5. Which of the following statements is FALSE?
A. For a perfectly competitive firm in the short run, marginal revenue will be equal to the average revenue.
B. In an oligopoly industry, firms make decisions taking into account the possible reactions of their competitors.
C. For a monopolist facing a linear demand curve, average revenue is
always less than marginal revenue.
D. A profit maximising monopoly firm with positive marginal costs of production charges a price in the region of the demand curve where demand is price elastic.
6. A firm produces 900 units of output. At this production level the firm’s marginal cost of production is £80 and the firm’s total cost of production is £45,000. At this level of production, the firm exhibits:
A. increasing returns to scale.
B. marginal returns to scale.
C. decreasing returns to scale.
D. constant returns to scale.
7. The market demand curve for GLeeMONEX, a powerful pharmaceutical, is given by the equation:
= 500 − 10 .
GLeeMONEX is produced at a constant marginal cost of £1 per unit. The firm Roritor Pharmaceuticals has a monopoly on GLeeMONEX and has set the price at £10 per unit. The deadweight loss created by Roritor’s monopoly is:
A. 810
B. 405
C. 490
D. 400
8. The demand curve for Pot Noodles among University of Sheffield students is depicted in the figure below. Peter estimates the price elasticity of demand to be −1.29 .
Based on Peter’s estimate, which point on the demand curve more likely reflects the current consumption of Pot Noodles by University of Sheffield students?
A. Point A
B. Point B
C. Either point A or point B are possible.
D. Neither point A nor point B are possible.
The topics below will not be covered on the January 2022 exam.
9. James offers Tania the opportunity to purchase a lottery ticket for £50. The lottery gives her the chance to win £200 with 30% probability and £0 with 70% probability.
Tania turns down the opportunity. According to the expected utility theory Tania’s behaviour is consistent with:
a. Risk loving preferences.
b. Risk averse preferences.
c. Risk neutral preferences.
d. None of the above.
10.Choose from the list below the policy which would is most likely to be in place to address the problem of adverse selection.
a. In housing markets, sellers are required to allow buyers to have an engineer conduct a structural inspection before the purchase is finalised.
b. Most standard life insurance will not cover death or injury due to
engaging in extreme sports such as rock-climbing or parasailing.
c. Car insurance is more expensive for younger drivers than for older drivers.
d. Most jobs in the civil service require that applicants hold a university degree.
SECTION B
11. Sunset Strip Husky is the only petrol station in the Canadian town of Kenora (the next petrol station is more than 50 miles away). The daily demand for petrol in Kenora can be represented by the following demand function:
= 10000 − 2000
where is the per-litre of petrol. The station has a marginal cost of = 1 per litre.
a) Calculate the price, quantity, and the resulting profits for Sunset Strip Husky’s monopoly. [8 marks]
We know that the price and quantity will be found by maximizing profits, which
can be found by setting MR=MC. First re-write the demand function in terms of
:
1
= 5 −
= 5 −
So
1
= 5 −
Setting MR=MC we get
1
5 − = 1
So ∗ = 4000 litres of petrol at a price of ∗ = 3 per litre. Notice that this
question does not give us fixed costs (only marginal costs, this was a mistake)
so our profits will not include any fixed costs that may exist:
= 4000 × 3 − 4000 × 1 = 8000.
Of course, if we had fixed costs, we could just subtract them from this total.
b) Calculate the deadweight loss associated with Sunset Strip Husky’s monopoly. Illustrate this on a graph with price on the vertical axis and quantity on the
horizontal axis. [6 marks]
The shaded area above shows the DWL associated with this monopoly. To
calculate this area, we need to first solve for the value of ? on the horizontal
axis. This is just the demand when price is 1:
= 10000 − 2000 × 1 = 8000
So the area of the shaded triangle is
= = 4000
2
So the DWL of the monopoly is $4000 worth of transactions for which the benefit
to consumers exceeds the cost of production.
12. Covid-19 has led to an unprecedented increase in the number of people who are working from home rather than in the office. This means that in Sheffield city centre (where office space is located), demand for coffee shops has dropped dramatically. However, in residential areas, such as Totley and Dore, demand for coffee shops has surged. Assuming the market for coffee shops is perfectly competitive, explain what is happening to the short-run profitability of these shops in city centres and residential suburbs. What do we expect to happen in the long-run if people continue to work from home post-Covid-19?
[20 marks]
An answer to this question should focus on competitive market in the short, versus
the long-run.
The story can be told as follows. Consider first what happens in the city centre. The
Covid pandemic has led to a large decrease in the number of workers who are
working from the office, instead these workers are working from home. This means
that in the city centre, where many offices are located, there will be a large decrease
in demand for coffees at during breaks and sandwiches at lunch time.
In the above figures, I describe how we expect movement to homeworking to impact
the market for coffee-shops in the city centre. Figure 1 shows the pre-Covid
equilibrium. As it is a competitive market, all firms are supplying such that their
average costs are covered, and the market price is equal to the marginal cost of
production (and the LAC of production).
The movement to homework during the pandemic is shown in Figure 2 as a leftward
shift in the market demand curve. This means that in the short-run, prices and
quantity of coffee sold in the city centre will decrease (from 1 to 2).
At the new price, 2 , firms in the market will not be covering their long-run average
costs. As this is not sustainable, over time some of the coffee shops will shut down
(shifting the SRS curve to the left, shown in Figure 3). This will decrease the quantity
of coffee sold in the city centre further, from 2 to 3 , and increase the price. The
price will increase until it is once again at its long-run equilibrium value where =
= .
The story for Dore and Totley will be very similar, but in the opposite direction.
Because these villages experience an increase in demand, as this is where the office
workers live, so the demand curve in Figure 1 will shift right. In the short run the
number of coffee shops does not change, but they respond to the demand increase
by increasing quantity and price. Therefore, in the short-run these village coffee
shops make supernormal profits. In the long-run, these profits entice new coffee
shops to open in the village, and the SRS curve shifts to the right. This will happen
until there are no longer supernormal profits to be made.
13. The market for Timbitsin Antigonish (another Canadian town) is described by the following inverse supply and inverse demand equations:
= 3000
= 10 − 0.01
Where is the number of Timbits supplied, is the number of Timbits demanded, and is the price per Timbit.
a) What is the equilibrium price and quantity in this market? [8 marks]
The equilibrium will be determined by the market clearing condition = .
First we need to rewrite the demand equation:
= 10 − 0.01
⇒ = 1000 − 100
And setting = we get
1000 − 100 = 3000
So ∗ = 0.32 and ∗ = 967 (rounded).
b) Calculate the consumer’s surplus and the producer’s surplus when the market is in equilibrium. Explain in words what each of these values represent.
Graphically we want to calculate:
From this figure it is straightforward to see what we want to calculate
= = 4680.28
2
= = 154.72
2
The consumer surplus shows the aggregate amount that consumers would have
been willing to pay over-and-above what they did pay for the Timbits. This can be
thought of as the total market value (or gains from trade) that consumers capture.
The producer surplus shows the aggregate amount that producers receive over
what they would have been willing to receive for the market quantity sold. This
can be thought of as the total market value (or gains from trade) that producers
capture.
c) The Canadian government decides that Timbitsshould be affordable for all Canadians. A price ceiling is introduced, such that suppliers are not allowed to charge more than $0.20 per Timbit. Calculate the deadweight loss that results from this policy. [6 marks]
The shaded area above shows the DWL created by this price ceiling. To
calculate this area we need to know the values of ?. The value can be found
by solving for the supply at 0.2:
= 3000 × 0.2 = 600
Now solve for the value for which -demand is 600:
= 10 − 0.01 × 600 = 4
So the DWL is
(967 − 600)(. 32 − .2) (967 − 600)(4 − .32)
= + = 697.3
2022-01-18