ECN 001A Lecture Notes - Lecture 7: Sunscreen, Midpoint Method, Insulin

Answer the following 24 questions.

1. The elasticity that measures how sensitive the buyers of a good are to a change in the price of another good is called:

a. price-elasticity of demand

b. income-elasticity of demand

c. cross-price-elasticity of demand

d. price-elasticity of supply

2. If the price of walnuts rises, many people would switch from consuming walnuts to consuming pecans. But if the price of salt rises, people would have difficulty purchasing something to use in its place. These examples illustrate the importance of

a. the availability of close substitutes in determining the price elasticity of demand.

b. a necessity versus a luxury in determining the price elasticity of demand.

c. the definition of a market in determining the price elasticity of demand.

d. the time horizon in determining the price elasticity of demand.

3. Suppose that Juan Carlos is filling out a survey that he received in the mail. The survey asks him what he would do if the price of his favorite toothpaste increased. Juan Carlos reports that he would switch to a different brand. The survey asks what he would do if the price of all kinds of toothpaste increased. Juan Carlos reports that he must use toothpaste, so he would have to adjust his spending elsewhere. These examples illustrate the importance of

a. changes in total revenue in determining the price elasticity of demand.

b. a necessity versus a luxury in determining the price elasticity of demand.

c. the definition (broad vs narrow) of a market in determining the price elasticity of demand.

d. the time horizon in determining the price elasticity of demand.

4. Suppose that gasoline prices increase dramatically this month. Lola commutes 100 miles to work each weekday. Over the next few months, Lola drives less on the weekends to try to save money. Within the year, she sells her home and purchases one only 10 miles from her place of employment. These examples illustrate the importance of

a. the availability of substitutes in determining the price elasticity of demand.

b. a necessity versus a luxury in determining the price elasticity of demand.

c. the definition of a market in determining the price elasticity of demand.

d. the time horizon in determining the price elasticity of demand.

5. When a smartphone manufacturer introduces a phone with new features (like a more powerful camera, more storage, a screen with better definition, or being waterproof) and advertises them, it is

a. trying to decrease buyers' price-elasticity of demand by differentiating the goods relative to the competition so that consumers perceive it as having no close substitutes in the market.

b. trying to decrease buyers' price-elasticity of demand by differentiating the goods relative to the competition so that consumers perceive it as having more substitutes in the market.

c. trying to increase buyers' price-elasticity of demand by differentiating the goods relative to the competition so that consumers perceive it as having more substitutes in the market.

d. trying to increase buyers' price-elasticity of demand by differentiating the goods relative to the competition so that consumers perceive it as having no close substitutes in the market.

6. Consider the following two alternative scenarios.

1) In scenario 1, the price of all smartphones increases by 10%.

2) In scenario 2, the price of Samsung smartphones increases by 10% while the price of all other smartphones stays the same as before.

Which of the following is true?

a. The quantity demanded of Samsung phones in scenario 2 falls by more, in percentage terms, than the quantity demanded of all phones in scenario 1.

b. The quantity demanded of Samsung phones in scenario 2 falls by less, in percentage terms, than the quantity demanded of all phones in scenario 1.

7. As more electric car models appear in the market, the price elasticity of demand for the models already in the market should

a. Stay the same. In other words, buyers' sensitivity to changes in the price of the existing cars does not change.

b. Increase. In other words, buyers' sensitivity to changes in the price of the existing cars increases.

c. Decrease. In other words, buyers' sensitivity to changes in the price of the product of the car decreases.

8. Demand for a good is likely to be flatter if

a. the good has many substitutes

b. the good is narrowly defined

c. we are considering the long run rather than the short run

d. the good is a luxury.

e. All of the above.

9. If the price elasticity of the demand for ice-cream is equal to 1.5, then

a. a 1% increase in price will lead to a 1.5% increase in quantity demanded.

b. a 1% increase in price will lead to a 150% fall in quantity demanded.

c. a 1% increase in price will lead to a 15% fall in quantity demanded.

d. a 1% increase in price will lead to a 1.5% fall in quantity demanded.

10. If the price elasticity of demand for oil is 0.7, then

a. Demand is elastic, buyers are relatively sensitive to price, and the demand curve is relatively flat.

b. Demand is elastic, buyers are relatively insensitive to price, and the demand curve is relatively flat.

c. Demand is inelastic, buyers are relatively insensitive to price, and the demand curve is relatively steep.

d. Demand is inelastic, buyers are relatively sensitive to price, and the demand curve is relatively flat.

11. Note: this question is not about calculating elasticity, but about showing that you know how to calculate a % change using the midpoint method in any circumstance.

A biology class at Q State University initially had 205 students. After the first test, enrollment dropped to 195 students. Using the midpoint method, the % change in the number of students is equal to

a. 10%

b. approximately 5.12%

c. approximately 4.88%

d. 5%

12. When the price of a good is $5, the quantity demanded is 100 units per month; when the price is $7, the quantity demanded is 80 units per month. Using the midpoint method, the price elasticity of demand is approximately

a. 0.22.

b. 0.67.

c. 1.33.

d. 1.50.

13. If the price elasticity of demand for hamburgers is 0.4, then a 20% increase in the price of hamburgers will lead to

a. an 8% fall in quantity demanded.

b. a 20% fall in quantity demanded.

c. a 0.4% fall in quantity demanded.

d. a 4% fall in quantity demanded.

14. If the price elasticity of demand for cruises is 1.4, a 1% decrease in the price of cruises will lead to a

a. A 1.4% increase in quantity demanded.

b. A 1% increase in quantity demanded.

c. A 1.4% decrease in quantity demanded.

d. A 1% decrease in quantity demanded.

15. A city wants to raise revenues to build a new municipal swimming pool next year. The mayor suggests that the city raise the price of admission to the existing municipal pools this year to raise revenues. The city manager suggests that the city lower the price of admission to raise revenues. Who is correct?

a. the mayor

b. the city manager

c. The answer depends on the price elasticity of demand.

d. The answer depends on the costs of construction of the new municipal swimming pool.

16. When demand is elastic, an increase in price will cause

a. an increase in total revenue.

b. a decrease in total revenue.

c. no change in total revenue.

d. not enough information.

17. Consider luxury weekend hotel packages in Las Vegas. When the price is $250, the quantity demanded is 2,000 packages per week. When the price is $280, the quantity demanded is 1,700 packages per week. Using the midpoint method, the price elasticity of demand is about

a. 1.43, and an increase in the price will cause hotels' total revenue to decrease.

b. 1.43, and an increase in the price will cause hotels' total revenue to increase.

c. 0.70, and an increase in the price will cause hotels' total revenue to decrease.

d. 0.70, and an increase in the price will cause hotels' total revenue to increase.

18. Suppose researchers at the University of Wisconsin discovered a new vitamin that increases the milk production of dairy cows. If the demand for milk is relatively inelastic, the discovery will

a. raise both price and total revenues.

b. lower both price and total revenues.

c. raise the price and lower total revenues.

d. lower price and raise total revenues.

19. When we calculate elasticities, whether the percent changes have a plus or a minus sign matters if we are calculating

a. Price elasticity of demand, because the signs give us information about whether the good is normal or inferior.

b. Income elasticity of demand, because the signs give us information about whether the good is normal or inferior.

c. Cross-price-elasticity of demand, because the signs give us information about whether the goods are substitutes or complements.

d. b and c are both correct.

20. Income elasticity of demand measures how

a. the quantity demanded changes as consumer income changes.

b. consumer purchasing power is affected by a change in the price of a good.

c. the price of a good is affected when there is a change in consumer income.

d. many units of a good a consumer can buy given a certain income level.

21. Last year, Carolyn bought 6 pairs of earrings when her income was $40,000. This year, her income is $52,000, and she purchased 7 pairs of earrings. Holding other factors constant, it follows that Carolyn's income elasticity of demand is about

a. 0.59, and Carolyn regards earrings as an inferior good.

b. 0.59, and Carolyn regards earrings as a normal good.

c. 1.7, and Carolyn regards earrings as an inferior good.

d. 1.7, and Carolyn regards earrings as a normal good.

22. Sandra purchases 5 pounds of coffee and 10 gallons of milk per month when the price of coffee is $10 per pound. She purchases 6 pounds of coffee and 12 gallons of milk per month when the price of coffee is $8 per pound. Sandra's cross-price elasticity of demand for milk with respect to the price of coffee

a. 0.82, and the goods are substitutes.

b. -0.82, and the goods are complements.

c. 1.22, and the goods are substitutes.

d. -1.22, and the goods are complements.

23. Supply of good is likely to be steeper (that is, more inelastic)

a. if sellers can cheaply make more units of the good on short notice.

b. in the long run.

c. in the short run.

d. if sellers have a large degree of flexibility to expand factory size.

24. When the price of a barrel of oil is $35, an oil fracking company is willing to produce 500 gallons per minute. If the price increased to $45, the company would be willing to produce 2500 gallons per minute. Using the midpoint method, calculate the company's price elasticity of supply.

 a. approximately 1.33

 b. 0.25

 c. approximately 5.33

d. approximately 0.188

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_____ 1. Suppose you make silver jewelry. If the price of silver falls, we would expect you to:

a. be willing and able to produce less jewelry than before at each possible price.

b. be willing and able to produce more jewelry than before at each possible price.

c. face greater demand for your jewelry.

d. face a weaker demand for your jewelry.

_____ 2. If suppliers expect the price of their product to fall in the future, then they will:

a. increase supply (supply curve shifts out) now.

b. decrease supply (supply curve shifts in) now.

c. increase supply in the future, but not now.

d. decrease supply in the future, but not now.

_____ 3. Consider the market for portable air conditioners, initially in equilibrium. When a heatwave strikes, the equilibrium price:

a. increases and equilibrium quantity decreases.

b. decreases, and the equilibrium quantity increases.

c. and quantity both increase.

d. and quantity both decrease.

_____ 4. Buyers can buy all they want to buy and sellers can sell all they want to sell at:

a. prices at and above the equilibrium price.

b. prices at and below the equilibrium price.

c. prices above and below the equilibrium price, but not at the equilibrium price.

d. the equilibrium price, but not at prices above or below the equilibrium price.

_____ 5. The law of supply and demand states that:

a. demand and supply curves shift out as time goes by.

b. the price of a goodwill rise in response to excess demand for that good.

c. when the supply curve for good shifts, the demand curve for that good shifts in response.

d. the equilibrium price of goodwill be rising more often than it will be falling.

_____ 6. If Doritos and Cheetos are substitutes, a rise in the price of Cheetos will cause:

a. the equilibrium quantity of Doritos to fall and the price of Doritos to rise.

b. the equilibrium quantity and price of Doritos to rise.

c. the equilibrium quantity and price of Doritos to fall.

d. the equilibrium quantity of Doritos to rise and the price of Doritos to fall.

_____ 7. New production technology is perfected that allows auto manufacturers to build an automobile using half the labor hours formerly needed. As a result:

a. the equilibrium quantity of automobiles increases and the price decreases.

b. the equilibrium quantity and price of automobiles increase.

c. the equilibrium quantity and price of automobiles decreases.

d. there is likely no change in the number of automobiles produced.

_____ 8. The U.S. government announces that it will raise the interest rate on college student loans beginning in January of next year. The immediate market impact is:

a. the demand curve for student loans shifts out.

b. the supply curve for student loans shifts out.

c. we anticipate that more student loans will be completed next year than this year.

d. all of the above are correct.

_____ 9. What curve shift produces a fall in price and increase in quantity exchanged?

a. An inward shift in the demand curve.

b. An inward shift in the supply curve.

c. An outward shift in the supply curve.

d. An outward shift in the demand curve.

_____ 10. We note that fewer motorcycles were sold this year than last and that the price is also lower. What event could have caused this outcome?

a. A technological change that improved the fuel efficiency of motorcycles.

b. A rise in the wages paid to motorcycle manufacturing workers.

c. A motorcycle craze due to the popularity of Sons of Anarchy.

d. Increasing concerns about health impacts from breathing motorcycle exhaust.

_____ 11. The price that results in quantity supplied equaling quantity demanded is the optimal (best) price because it:

a. maximizes the combined welfare of buyers and sellers.

b. maximizes the cost of the seller.

c. minimizes the expenditure of buyers.

d. all of the above are correct.

_____ 12. Consumer surplus is the:

a. quantity of good consumers get without paying anything.

b. amount a consumer pays minus the amount the consumer is willing to pay.

c. amount a consumer is willing to pay minus the amount the consumer pays.

d. value of a good to a consumer.

_____ 13. In a market, the marginal buyer is the one:

a. whose willingness to pay is higher than all other buyers and potential buyers.

b. whose willingness to pay is lower than all other buyers and potential buyers.

c. who is willing to buy exactly one unit of the good.

d. who would be the first to leave the market if the price were any higher.

_____ 14. If a consumer is willing and able to pay $20 for a particular good and if she actually pays $16 for the good, then her consumer surplus is:

a. $4.

b. $16.

c. $20.

d. $36.

_____ 15. Suppose there is an early freeze in California that reduces the size of the orange crop. What happens to consumer surplus in the market for oranges?

a. Consumer surplus increases.

b. Consumer surplus decreases.

c. Consumer surplus is not affected by this change.

d. We would have to know whether the demand for oranges is elastic or inelastic.

_____ 16. Producer surplus is the area on a supply/demand graph:

a. under the supply curve.

b. between the supply and demand curves.

c. below the price line and above the supply curve.

d. under the demand curve and above the price line.

_____ 17. Economists typically measure economic efficiency using:

a. total producer and consumer surplus.

b. profits to firms.

c. the quantity supplied by sellers.

d. the price paid by buyers.

_____ 18. Which of the following statements is correct?

a. Efficiency and equality are both maximized when total surplus is maximized.

b. Efficiency deals with the size of the economic pie; equality with how fairly the pie is sliced.

c. Efficiency is more difficult to evaluate than equality.

d. Equality is judged on positive grounds; efficiency requires normative judgments.

_____ 19. The price elasticity of demand measures how much:

a. quantity demanded a response to changes in price.

b. quantity demanded a response to changes in income.

c. price responds to a change in demand.

d. Both a and c are correct

_____ 20. Goods with many close substitutes tend to have:

a. less elastic demands.

b. more elastic demands.

c. price elasticities of demand that are unit elastic.

d. income elasticities that are negative.

Short Answer Questions:

All of the following questions are based on the data shown here for coffee demand and supply at a fictional Columbus coffee shop called Go-bucks.

Price Quantity Quantity

per Cup Demanded Supplied

$1.60 1,700 1,220

$1.80 1,555 1,300

$2.00 1,400 1,400

$2.20 1,235 1,520

$2.40 1,060 1,660

$2.60 875 1,820

_____ 21. (6 points) Using the mid-point formula, calculate the price elasticity of demand as the price increases from $1.60 to $1.80.

_____ 22. (6 points) Repeat the calculation of the price elasticity of demand, this time for a price increase from $1.80 to $2.00.

_____ 23. (6 points) Repeat the calculation of the price elasticity of demand, this time for a price increase from $2.40 to $2.60.

24. (4 points) Over which price range is demand inelastic? Over which price range is demand elastic? Does this follow the trend noted in class?

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_____ 25. (6 points) Turning to the supply side, calculate the price elasticity of supply as the price increases from $2.20 to $2.40.

26. (2 points) How would you describe the price elasticity of supply over this range?

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