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Micro Chapter 7 Consumer Choice and Elasticity. This chapter is an extension of the first part of Chapter 3 on demand and consumer theory Refer back to.

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Presentation on theme: "Micro Chapter 7 Consumer Choice and Elasticity. This chapter is an extension of the first part of Chapter 3 on demand and consumer theory Refer back to."— Presentation transcript:

1 Micro Chapter 7 Consumer Choice and Elasticity

2 This chapter is an extension of the first part of Chapter 3 on demand and consumer theory Refer back to your Chapter 3 notes and mentally combine them with Chapter 7 notes

3 6 Learning Goals 1)List the key factors influencing consumer behavior (repeat from Chapter 3) 2)Apply the concept of marginal utility to determine how a demand curve is derived (repeat from Chapter 3) 3)Define, calculate, and graph elasticity of demand 4)Relate demand elasticity to total revenue 5)Define and calculate income elasticity 6)Define and graph elasticity of supply

4 Elasticity of Demand

5 Law of demand states that if price rises (falls), quantity demanded falls (rises) Elasticity gives us more information about the consumer Price elasticity seeks to quantify how much quantity demanded falls (rises)

6 Class Activity: Draw two demand curves side by side. Increase price by the same amount in each graph. Draw the first demand curve illustrating a small reduction in quantity demanded. Draw the second demand curve illustrating a large reduction in quantity demanded.

7 Graphs: Watch content video: Inelastic-Elastic demand curves

8 Other questions to consider: By how much does price need to rise to decrease quantity demanded by X%? By how much does price need to fall to increase quantity demanded by Y%?

9 Price elasticity of demand= percentage change in quantity demanded / percentage change in price Elasticity = % Δ Q d % Δ P

10 Values of price elasticity If ε > 1, then elastic Consumers change their behavior a lot If ε < 1, then inelastic Consumers change their behavior a little If ε = 1, then unitary elastic Consumers dont change their behavior

11 Key point: Price elasticity is NOT the slope of the demand curve –A straight-line demand curve will have constant slope but a different elasticity at every point

12 I often do a survey of my students to see if their demand for places at the university responds to prices. The price of places at the university is the tuition charged. I offer students the possibility of zero tuition increase for next year, a 5 percent increase for next year, and a 10 percent increase. Each student is then asked whether he or she will return next year. I recently got the following results: For a 5 percent tuition increase, the number of students returning would decrease by 2.2 percent, implying a price elasticity of demand equaling For a 10 percent tuition increase, however, the number returning would fall by 11.8 percent, implying an elasticity of The demand curve is surely downward sloping. Not only does the number of places demanded decline when tuition rises more; the responsiveness of demand- the price elasticity of demand- is greater in percentage terms when the university tries to raise tuition by higher amounts. Thats not surprising: Substitutes that suddenly become slightly cheaper dont affect behavior proportionately as much as substitutes that suddenly become relatively a lot cheaper. Q: Who is likely to be more inelastic, freshmen or juniors? Why?

13 Q7.1 If a large percentage increase in the price of a good results in a small percentage reduction in the quantity demanded of the good, demand is said to be 1.unitary elastic. 2.relatively inelastic. 3.relatively elastic. 4.perfectly elastic.

14 Q7.2 When economists say the demand for a good is highly inelastic, they mean that 1.even if the price rose substantially, suppliers would be unwilling to offer much more of the good. 2.the facilities utilized by producers of the good are inflexible; producers cannot easily expand their facilities, even in the long run. 3.consumers will respond to a change in the price of the good by purchasing substantially more of it. 4.a large (percentage) change in the price of a good will result in only a small (percentage) change in the quantity demanded.

15 What determines elasticity? (1) Availability of substitutes –More substitutes, more elastic (more responsive) (2) Share of budget –Greater share, more elastic (3) Time –More time, more elastic

16 Q7.3 Members of Alpha fraternity have developed a strong liking for Coca-Cola. Beta fraternity members buy the same amount of Coke but believe Pepsi is just about as good. From this, we can infer that 1.Alpha members will not care what the price of Coke is. 2.compared to Alpha members, Betas will have a smaller price elasticity of demand for Coke. 3.compared to Alpha members, Betas will have a larger price elasticity of demand for Coke. 4.Alpha members will increase their purchases by a larger amount of Pepsi than Beta members in response to a "50 cents off" sale on a case of Pepsi.

17 How Demand Elasticity and Price Changes Affect Total Expenditures (or Revenues) on a Product

18 Impact of lower price on total consumer expenditures or a firms total revenue increase decrease -- unchanged -- Price elasticity of demand Elastic Inelastic Unitary Elastic Elasticity coefficient (in absolute value) 1 to 0 to 1 1 Impact of higher price on total consumer expenditures or a firms total revenue decrease increase -- unchanged --

19 Dont memorize this chart! Use it as a tool Think about what elasticity tells us and then apply it to total revenue

20 Total Revenue (TR) to the firm is Total Expenditure (TE) by the consumer. TR = TE = P x Q If elastic and price falls: P x Q = TR –Lower price and lots more is bought, Q dominates equation If elastic and price rises: P x Q = TR –Raise price and lots less is bought, Q dominates equation If inelastic and price falls: P x Q = TR –Lower price and a little more is bought, P dominates equation If inelastic and price rises: P x Q = TR –Raise price and a little less is bought, P dominates equation

21 A different way to look at this: 4 graphs Watch content video: Elasticity and TR

22 The local airport in Austin, Texas, opened in 1999 with on- site parking, priced from $18 per day for garage parking to $6 per day for distant uncovered parking. The lots were so crowded that soon the Airport Authority built an additional lot. By 2002, off-site parking places had opened up, offering covered parking for $8 per day, and some offering three- minute shuttle service to the terminal. Not surprisingly, this entry of new competitors into the parking market has left many on-site places empty, and the airports parking revenues this year have fallen from $22 million to $18 million. If the Airport Authority is smart, it would think about what its demand elasticity is, lower prices if it believes demand is elastic, not lower them, and maybe even raise them (especially on garage parking) if it believes demand is inelastic. The evidence suggests management believes that the demand is elastic for the garage parking, because in 2004 they lowered the price for garage parking to $15 per day. Q: For which part of the airport parking areas is the demand likely to be more or less elastic, the garage parking or the uncovered distant parking? In light of your beliefs about this question, how would you alter prices?

23 Q7.4 Suppose ε = 0.52 and the firm raises price. What happens to TR? 1.TR rises 2.TR falls 3.TR remains constant

24 Q7.5 Suppose the firm wants to raise TR and it knows demand is elastic. What should the firm do? 1.Raise price 2.Lower price 3.Keep price the same

25 Q7.6 (MA) In which of the following cases will the total spending on a good decrease? 1.Demand is elastic, and price decreases. 2.Demand is elastic, and price increases. 3.Demand is inelastic, and price increases. 4.Demand is inelastic, and price decreases.

26 Income Elasticity

27 Price elasticity measures the change in consumer purchases when price changes Income elasticity measures the change in consumer purchases when income changes Income Elasticity = % Δ Q d % Δ I % Δ I

28 Values of income elasticity If positive, consumers buy more when income rises Normal good - a good that consumers will buy more of when income rises If negative, consumers buy less when income rises Inferior good - a good that consumers will buy less of when income rises

29 Price Elasticity of Supply

30 Price elasticity of supply measures the responsiveness of quantity supplied to price changes How much does quantity supplied increase (or decrease) when price rises (or falls)?

31 Graphs: Watch content video: Inelastic-Elastic supply curves

32 Question Answers: Q7.1 = 2 Q7.2 = 4 Q7.3 = 3 Q7.4 = 1 Q7.5 = 2 Q7.6 = 2 & 4


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