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Elasticity and its Application 탄력성과 그 응용

5. Elasticity and its Application 탄력성과 그 응용. E conomics. P R I N C I P L E S O F. N. Gregory Mankiw. Premium PowerPoint Slides by Ron Cronovich. In this chapter, look for the answers to these questions:.

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Elasticity and its Application 탄력성과 그 응용

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  1. 5 Elasticity and its Application탄력성과 그 응용 Economics P R I N C I P L E S O F N. Gregory Mankiw Premium PowerPoint Slides by Ron Cronovich

  2. In this chapter, look for the answers to these questions: • What is elasticity? What kinds of issues can elasticity help us understand? 탄력성이란? 탄력성은 어떤 문제를 이해하는 데 도움이 되는가? • What is the price elasticity of demand? 수요의 가격탄력성이란? How is it related to the demand curve? 수요곡선과 어떻게 관련되는가? How is it related to revenue & expenditure? 수입 및 지출과는 어떻게 관련되는가? • What is the price elasticity of supply? 공급의 가격탄력성이란? How is it related to the supply curve? 공급곡선과 어떻게 관련되는가? • What are the income and cross-price elasticities of demand? 수요의 소득탄력성 및 수요의 교차탄력성이란? 1

  3. You design websites for local businesses. 당신은 지역업체들에게 웹사이트를 디자인해준다. You charge $200 per website, and currently sell 12 websites per month. 웹사이트당 $200를 받는데 현재 1달에 12개를 판다. Your costs are rising (including the opportunity cost of your time), so you consider raising the price to $250. (당신의 시간비용을 포함한) 비용이 오르고 있어 가격을 $250로 올리는 것을 고려하고 있다. The law of demand says that you won’t sell as many websites if you raise your price. 수요의 법칙에 의하면, 가격을 올리면 종전처럼 많이 팔지 못할 것이다.How many fewer websites? How much will your revenue fall, or might it increase? 얼마나 적게 팔까? 수입은 얼마나 감소할까, 아니면 증가할 수도 있을까? A scenario… 0 2

  4. Elasticity 탄력성 Basic idea: 기본개념Elasticity measures how much one variable responds to changes in another variable. 탄력성은 한 변수가 다른 변수의 변화에 얼마나 크게 반응하는가를 측정한다. One type of elasticity measures how much demand for your websites will fall if you raise your price. 가격을 올리면 웹사이트에 대한 수요가 얼마나 떨어질 것인가도 탄력성의 하나 Definition: 정의Elasticity is a numerical measure of the responsiveness of Qd or Qs to one of its determinants. 탄력성이란 수요량 또는 공급량이 그 결정요인 중 하나에 대해 반응하는 정도를 숫자로 측정한 것 0 ELASTICITY AND ITS APPLICATION

  5. Price Elasticity of Demand Price elasticity of demand measures how much Qd responds to a change in P. 수요의 가격탄력성은 수요량이 가격 변화에 얼마나 반응하는가를 측정 Percentage change in Qd Price elasticity of demand = Percentage change in P 0 • Loosely speaking, it measures the price-sensitivity of buyers’ demand. 쉽게 말해, 구매자 수요의 가격 민감도를 측정 ELASTICITY AND ITS APPLICATION

  6. Price Elasticity of Demand Price elasticity of demand equals P Percentage change in Qd Price elasticity of demand P1 = P2 Percentage change in P D Q Q1 Q2 15% = 1.5 10% 0 Example: P rises by 10% Q falls by 15% ELASTICITY AND ITS APPLICATION

  7. Price Elasticity of Demand Along a D curve, P and Q move in opposite directions, which would make price elasticity negative. 수요곡선상에서 P와 Q는 반대방향으로 움직이므로 가격탄력성 값은 마이너스 We will drop the minus sign and report all price elasticities as positive numbers. 모든 가격탄력성은 마이너스 부호를 빼고 표시 P Percentage change in Qd Price elasticity of demand P1 = P2 Percentage change in P D Q Q1 Q2 0 ELASTICITY AND ITS APPLICATION

  8. Calculating Percentage Changes P end value – start value x 100% B start value D $250 A Q $200 8 12 0 Standard method of computing the percentage (%) change: % 변화를 계산하는 표준 방식 Demand for your websites Going from A to B, the % change in P equals ($250–$200)/$200 = 25% ELASTICITY AND ITS APPLICATION

  9. Calculating Percentage Changes P B D $250 A Q $200 8 12 0 Problem: The standard method gives different answers depending on where you start. 표준방식으로 계산하면 어디서 시작하느냐에 따라 답이 달라짐 Demand for your websites From A to B, P rises 25%, Q falls 33%,elasticity = 33/25 = 1.33 From B to A, P falls 20%, Q rises 50%, elasticity = 50/20 = 2.50 ELASTICITY AND ITS APPLICATION

  10. Calculating Percentage Changes So, we instead use the midpoint method: 중간점 방식 end value – start value x 100% midpoint 0 • The midpoint is the number halfway between the start & end values, the average of those values. 중간점은 최초값과 최종값의 중간, 즉 평균 • It doesn’t matter which value you use as the “start” and which as the “end” – you get the same answer either way! 어느 것을 최초값으로 사용하든 상관없이 양방향 동일한 답을 얻게 됨 ELASTICITY AND ITS APPLICATION

  11. Calculating Percentage Changes Using the midpoint method, the % change in P equals 중간점 방식을 이용하면 P의 % 변화는 = 40.0% x 100% 12 – 8 $250 – $200 10 = 22.2% x 100% $225 40/22.2 = 1.8 0 • The % change in Q equals Q의 % 변화는 • The price elasticity of demand equals 수요의 가격탄력성은 ELASTICITY AND ITS APPLICATION

  12. A C T I V E L E A R N I N G 1Calculate an elasticity Use the following information to calculate the price elasticity of demand for hotel rooms: if P = $70, Qd = 5000 if P = $90, Qd = 3000 11

  13. 50% = 2.0 25% A C T I V E L E A R N I N G 1Answers Use midpoint method to calculate % change in Qd (5000 – 3000)/4000 = 50% % change in P ($90 – $70)/$80 = 25% The price elasticity of demand equals 12

  14. What determines price elasticity? To learn the determinants of price elasticity, we look at a series of examples.가격탄력성의 결정요인을 학습하기 위해 몇가지 예를 살펴봄Each compares two common goods. 각 예는 평범한 두 재화를 비교 In each example: Suppose the prices of both goods rise by 20%. 두 재화 모두 가격이 20% 상승한다고 가정 The good for which Qd falls the most (in percent) has the highest price elasticity of demand. Which good is it? Why? 수요량이 가장 크게 감소하는 재화가 가격탄력성이 가장 높은데, 어느 재화인가? 왜 그런가? What lesson does the example teach us about the determinants of the price elasticity of demand? 이예를 통해 수요의 가격탄력성의 결정요인에 관해 무엇을 배울 수 있는가? 0 ELASTICITY AND ITS APPLICATION

  15. EXAMPLE 1:Breakfast cereal vs. Sunscreen The prices of both of these goods rise by 20%. For which good does Qd drop the most? Why? 어느 재화의 수요량이 크게 감소하는가? 왜 그런가? Breakfast cereal has close substitutes (e.g., pancakes, Eggo waffles, leftover pizza), so buyers can easily switch if the price rises. 아침식사용 시리얼은 밀접한 대체재들이 있으므로 가격이 오르면 다른 재화로 쉽게 전환 가능 Sunscreen has no close substitutes, so consumers would probably not buy much less if its price rises. 선스크린은 밀접한 대체재가 없고, 따라서 가격이 올라도 크게 줄일 수 없을 것 Lesson: Price elasticity is higher when close substitutes are available.밀접한 대체재가 있으면 가격탄력성이 높다 0 ELASTICITY AND ITS APPLICATION

  16. EXAMPLE 2:“Blue Jeans” vs. “Clothing” 청바지 vs. 의류 The prices of both goods rise by 20%. For which good does Qd drop the most? Why? For a narrowly defined good such as blue jeans, there are many substitutes (khakis, shorts, Speedos). 청바지처럼 좁게 정의된 재화는 많은 대체재를 가짐 There are fewer substitutes available for broadly defined goods. 넓게 정의된 재화는 대체재를 구하기 어려움(There aren’t too many substitutes for clothing, other than living in a nudist colony.) 나체촌이 아니라면 의류의 대체재는 별로 없을 것 Lesson: Price elasticity is higher for narrowly defined goods than broadly defined ones. 좁게 정의된 재화가 넓게 정의된 재화보다 가격탄력성이 높음 0 ELASTICITY AND ITS APPLICATION

  17. EXAMPLE 3:Insulin vs. Caribbean Cruises The prices of both of these goods rise by 20%. For which good does Qd drop the most? Why? To millions of diabetics, insulin is a necessity. A rise in its price would cause little or no decrease in demand. 당뇨병 환자에게 인슐린은 필수재임. 가격이 올라도 수요는 거의 변화가 없을 것 A cruise is a luxury. If the price rises, some people will forego it. 크루즈 여행은 사치재임. 가격이 오르면 일부 사람들은 포기할 것 Lesson: Price elasticity is higher for luxuries than for necessities.사치재가 필수재보다 가격탄력성이 높음 0 ELASTICITY AND ITS APPLICATION

  18. EXAMPLE 4:Gasoline in the Short Run vs. Gasoline in the Long Run The price of gasoline rises 20%. Does Qd drop more in the short run or the long run? Why? 수요량이 단기에 더 많이 감소하는가 아니면 장기에 더 많이 감소하는가? There’s not much / people can do in the short run, other than ride the bus or carpool. 단기적으로는 버스를 타거나 카풀 외에는 할 수 있는 일이 별로 없음 In the long run, people can buy smaller cars or live closer to where they work. 장기적으로는 작은 차를 사거나 직장 근처에 거주할 수 있음 Lesson: Price elasticity is higher in the long run than the short run.단기보다 장기에 가격탄력성이 높음 0 ELASTICITY AND ITS APPLICATION

  19. The Determinants of Price Elasticity: A Summary The price elasticity of demand depends on: the extent to which close substitutes are available whether the good is a necessity or a luxury how broadly or narrowly the good is defined the time horizon – elasticity is higher in the long run than the short run 0 ELASTICITY AND ITS APPLICATION

  20. The Variety of Demand Curves The price elasticity of demand is closely related to the slope of the demand curve. 수요의 가격탄력성은 수요곡선의 기울기와 밀접하게 관련됨 Rule of thumb: 어림잡아 (눈대중으로), 경험상The flatter the curve, the bigger the elasticity. 수요곡선이 완만할수록 탄력성은 커진다The steeper the curve, the smaller the elasticity. 수요곡선이 가파를수록 탄력성은 작아진다 Five different classifications of D curves.… D곡선의 다섯 가지 분류 0 ELASTICITY AND ITS APPLICATION

  21. Perfectly inelastic demand(one extreme case) 완전비탄력적 수요 % change in Q Price elasticity of demand = = % change in P P D P1 P2 Q Q1 0 0% = 0 10% D curve: Vertical 수직 Consumers’ price sensitivity: none P falls by 10% Elasticity: 0 Q changes by 0% ELASTICITY AND ITS APPLICATION

  22. Inelastic demand 비탄력적 수요 % change in Q Price elasticity of demand = = % change in P P P1 P2 Q D Q1 Q2 0 < 10% < 1 10% D curve: relatively steep 비교적 가파름 Consumers’ price sensitivity: relatively low 비교적 낮음 P falls by 10% Elasticity: < 1 Q rises less than 10% ELASTICITY AND ITS APPLICATION

  23. Unit elastic demand 단위탄력적 수요 % change in Q Price elasticity of demand = = % change in P P P1 D P2 Q Q1 Q2 0 10% = 1 10% D curve: intermediate slope 중간 기울기 Consumers’ price sensitivity: intermediate P falls by 10% Elasticity: 1 Q rises by 10% ELASTICITY AND ITS APPLICATION

  24. Elastic demand 탄력적 수요 % change in Q Price elasticity of demand = = % change in P P P1 D P2 Q Q1 Q2 0 > 10% > 1 10% D curve: relatively flat 비교적 완만 Consumers’ price sensitivity: relatively high 비교적 높음 P falls by 10% Elasticity: > 1 Q rises more than 10% ELASTICITY AND ITS APPLICATION

  25. Perfectly elastic demand(the other extreme) 완전탄력적 수요 % change in Q Price elasticity of demand = = % change in P P D Q Q1 Q2 0 any % = infinity 0% D curve: Horizontal 수평 P1 P2 = Consumers’ price sensitivity: Extreme 극단적 P changes by 0% Elasticity: Infinity 무한대 Q changes by any % ELASTICITY AND ITS APPLICATION

  26. Elasticity of a Linear Demand Curve 직선 수요곡선의 탄력성 The slope of a linear demand curve is constant, but its elasticity is not. 직선 수요곡선의 기울기는 일정하지만, 탄력성은 일정하지 않다 67% 200% 40% E= E= E= = 1.0 = 0.2 = 5.0 P 67% 40% 200% $30 20 10 $0 Q 0 20 40 60 0 ELASTICITY AND ITS APPLICATION

  27. Price Elasticity and Total Revenue 가격탄력성과 총수입 Continuing our scenario, if you raise your price from $200 to $250, would your revenue rise or fall? 가격을 $200에서 $250로 올리면 수입은 증가할까 아니면 감소할까? Revenue = P x Q A price increase has two effects on revenue: 가격상승은 수입에 두 가지 효과 Higher P means more revenue on each unit you sell. 한 단위당 수입 증가를 의미 But you sell fewer units (lower Q), due to Law of Demand. 수요의 법칙으로 인해 판매량 감소 Which of these two effects is bigger? 두 효과 중 어느 것이 클까? It depends on the price elasticity of demand. 그것은 수요의 가격탄력성에 의존 0 ELASTICITY AND ITS APPLICATION

  28. Price Elasticity and Total Revenue If demand is elastic, then price elast. of demand > 1 수요가 탄력적이면 수요의 가격탄력성은 1보다 크다 % change in Q > % change in P The fall in revenue from lower Q is greater than the increase in revenue from higher P, so revenue falls. 수량감소에 따른 수입 감소가 가격상승에 따른 수입 증가보다 커서 수입은 감소 Percentage change in Q Price elasticity of demand = Percentage change in P 0 Revenue = P x Q ELASTICITY AND ITS APPLICATION

  29. Price Elasticity and Total Revenue Elastic demand(elasticity = 1.8) P If P = $200, Q = 12 and revenue = $2400. $250 $200 If P = $250, Q = 8 and revenue = $2000. D Q 12 8 0 increased revenue due to higher P 가격인상으로 인한 수입증가 Demand for your websites lost revenue due to lower Q 판매량 감소로 인한 수입감소 When D is elastic, a price increase causes revenue to fall. D가 탄력적이면, 가격인상은 수입을 떨어뜨린다 ELASTICITY AND ITS APPLICATION

  30. Price Elasticity and Total Revenue If demand is inelastic, then price elast. of demand < 1 수요가 비탄력적이면 수요의 가격탄력성은 1보다 작다 % change in Q < % change in P The fall in revenue from lower Q is smaller than the increase in revenue from higher P, so revenue rises. 수량감소에 따른 수입 감소가 가격상승에 따른 수입 증가보다 작아서 수입은 증가 In our example, suppose that Q only falls to 10 (instead of 8) when you raise your price to $250. 예에서 가격을 $250로 올릴 때 수량이 (8이 아니라)10으로만 떨어진다고 가정 Percentage change in Q Price elasticity of demand = Percentage change in P 0 Revenue = P x Q ELASTICITY AND ITS APPLICATION

  31. Price Elasticity and Total Revenue Now, demand is inelastic: elasticity = 0.82 P If P = $200, Q = 12 and revenue = $2400. $250 $200 D If P = $250, Q = 10 and revenue = $2500. Q 12 10 0 increased revenue due to higher P Demand for your websites lost revenue due to lower Q When D is inelastic, a price increase causes revenue to rise. ELASTICITY AND ITS APPLICATION

  32. A C T I V E L E A R N I N G 2Elasticity and expenditure/revenue A. Pharmacies raise the price of insulin by 10%. Does total expenditure on insulin rise or fall? B. As a result of a fare war, the price of a luxury cruise falls 20%. Does luxury cruise companies’ total revenue rise or fall? 31

  33. A C T I V E L E A R N I N G 2Answers A. Pharmacies raise the price of insulin by 10%. Does total expenditure on insulin rise or fall? Expenditure = P x Q Since demand is inelastic, Q will fall less than 10%, so expenditure rises. 32

  34. A C T I V E L E A R N I N G 2Answers B. As a result of a fare war, the price of a luxury cruise falls 20%. Does luxury cruise companies’ total revenue rise or fall? Revenue = P x Q The fall in P reduces revenue, but Q increases, which increases revenue. Which effect is bigger? Since demand is elastic, Q will increase more than 20%, so revenue rises. 33

  35. APPLICATION: Does Drug Interdiction Increase or Decrease Drug-Related Crime?마약금지가 마약관련 범죄를 증가시킬까 감소시킬까? One side effect of illegal drug use is crime: Users often turn to crime to finance their habit. 불법 마약복용의 부작용 중 하나는 범죄: 돈을 마련하기 위해 범죄를 저지르게 됨 We examine two policies designed to reduce illegal drug use and see what effects they have on drug-related crime. 불법 마약복용을 감소시키기 위해 고안된 두 정책을 검토, 마약관련 범죄에 어떤 효과를 가지는지 살펴봄 For simplicity, we assume the total dollar value of drug-related crime equals total expenditure on drugs. 단순화를 위해 마약관련 범죄의 총비용이 마약에 대한 총지출과 같다고 가정 Demand for illegal drugs is inelastic, due to addiction issues. 중독성으로 인해 불법 마약에 대한 수요는 비탄력적 0 ELASTICITY AND ITS APPLICATION

  36. Policy 1: Interdiction new value of drug-related crime Price of Drugs S2 D1 S1 P2 initial value of drug-related crime P1 Quantity of Drugs Q1 Q2 0 Interdiction reduces the supply of drugs. 금지는 마약공급을 감소시킴 Since demand for drugs is inelastic, P rises proportionally more than Q falls. 수요가 비탄력적이므로 수량 감소보다 가격상승 비율이 큼 Result: an increase in total spending on drugs, and in drug-related crime 마약에 대한 지출 및 관련 범죄 증가 ELASTICITY AND ITS APPLICATION

  37. Policy 2: Education new value of drug-related crime Price of Drugs D2 D1 S initial value of drug-related crime P1 P2 Quantity of Drugs Q2 Q1 0 Education reduces the demand for drugs. 교육은 마약수요를 감소시킴 P and Q fall. 가격과 수량 하락 Result:A decrease in total spending on drugs, and in drug-related crime. 결과: 마약에 대한 총지출 및 마약관련 범죄 감소 ELASTICITY AND ITS APPLICATION

  38. Price Elasticity of Supply Price elasticity of supply measures how much Qs responds to a change in P. 공급의 가격탄력성은 공급량이 가격 변화에 얼마나 반응하는지를 측정 Percentage change in Qs Price elasticity of supply = Percentage change in P 0 • Loosely speaking, it measures sellers’ price-sensitivity. 쉽게 말해, 판매자의 가격 민감도를 측정 • Again, use the midpoint method to compute the percentage changes. 다시 한번, % 변화를 계산하기 위해 중간점 방식을 사용 ELASTICITY AND ITS APPLICATION

  39. Price Elasticity of Supply Price elasticity of supply equals P S Percentage change in Qs Price elasticity of supply = P2 Percentage change in P P1 Q Q1 Q2 16% = 2.0 8% 0 Example: P rises by 8% Q rises by 16% ELASTICITY AND ITS APPLICATION

  40. The Variety of Supply Curves The slope of the supply curve is closely related to price elasticity of supply. 공급곡선의 기울기는 공급의 가격탄력성과 밀접하게 관련됨 Rule of thumb: 어림잡아The flatter the curve, the bigger the elasticity. 공급곡선이 완만할수록 탄력성은 커진다 The steeper the curve, the smaller the elasticity. 공급곡선이 가파를수록 탄력성은 작아진다 Five different classifications.… 다섯 가지 분류 0 ELASTICITY AND ITS APPLICATION

  41. Perfectly inelastic (one extreme) 완전비탄력적 % change in Q Price elasticity of supply = = % change in P P S P2 Q 0 0% = 0 10% S curve: vertical Sellers’ price sensitivity: P1 none P rises by 10% Elasticity: Q1 0 Q changes by 0% ELASTICITY AND ITS APPLICATION

  42. Inelastic 비탄력적 % change in Q Price elasticity of supply = = % change in P P S P2 Q Q2 0 < 10% < 1 10% S curve: relatively steep Sellers’ price sensitivity: P1 relatively low P rises by 10% Elasticity: Q1 < 1 Q rises less than 10% ELASTICITY AND ITS APPLICATION

  43. Unit elastic 단위탄력적 % change in Q Price elasticity of supply = = % change in P P S P2 Q Q2 0 10% = 1 10% S curve: intermediate slope Sellers’ price sensitivity: P1 intermediate P rises by 10% Elasticity: Q1 = 1 Q rises by 10% ELASTICITY AND ITS APPLICATION

  44. Elastic 탄력적 % change in Q Price elasticity of supply = = % change in P P S P2 Q Q2 0 > 10% > 1 10% S curve: relatively flat Sellers’ price sensitivity: P1 relatively high P rises by 10% Elasticity: Q1 > 1 Q rises more than 10% ELASTICITY AND ITS APPLICATION

  45. Perfectly elastic(the other extreme) 완전탄력적 % change in Q Price elasticity of supply = = % change in P P S Q Q2 Q1 0 any % = infinity 0% S curve: horizontal P1 P2 = Sellers’ price sensitivity: extreme P changes by 0% Elasticity: infinity Q changes by any % ELASTICITY AND ITS APPLICATION

  46. The Determinants of Supply Elasticity The more easily sellers can change the quantity they produce, the greater the price elasticity of supply. 공급자들이 생산량을 쉽게 변경할 수 있을수록 공급의 가격탄력성은 커짐 Example: Supply of beachfront property is harder to vary and thus less elastic than supply of new cars. 해변토지의 공급은 변화가 어렵고 따라서 신차의 공급보다 탄력성이 낮음 For many goods, price elasticity of supply is greater in the long run than in the short run, because firms can build new factories, or new firms may be able to enter the market. 많은 재화에 있어, 공급의 가격탄력성이 단기보다 장기에 더 큰데, 그 이유는 기업이 새 공장을 건설하거나 새로운 기업이 시장에 진입할 수 있기 때문임 ELASTICITY AND ITS APPLICATION

  47. A C T I V E L E A R N I N G 3Elasticity and changes in equilibrium • The supply of beachfront property is inelastic. The supply of new cars is elastic. • Suppose population growth causes demand for both goods to double (at each price, Qd doubles). • For which product will P change the most? • For which product will Q change the most? 46

  48. P S D1 D2 B P2 P1 A Q Q1 Q2 A C T I V E L E A R N I N G 3Answers Beachfront property (inelastic supply): When supply is inelastic, an increase in demand has a bigger impact on price than on quantity. 47

  49. P D1 D2 S B P2 A P1 Q Q2 Q1 A C T I V E L E A R N I N G 3Answers New cars(elastic supply): When supply is elastic, an increase in demand has a bigger impact on quantity than on price. 48

  50. How the Price Elasticity of Supply Can Vary Supply often becomes less elastic as Q rises, due to capacity limits. 생산능력의 한계로 인해 생산이 늘 때 공급의 탄력성이 떨어지기도 함 P S $15 12 4 $3 Q 100 200 500 525 0 elasticity < 1 elasticity > 1 ELASTICITY AND ITS APPLICATION

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