微观经济学individualandmarketdemand(编辑修改稿)

微观经济学individualandmarketdemand(编辑修改稿)内容摘要：

69。 2020 Pearson Education, Inc. Chapter 4 45 Price Elasticity of Demand Isoelastic Demand When price elasticity of demand is constant along the entire demand curve Demand curve is bowed inward (not linear) 169。 2020 Pearson Education, Inc. Chapter 4 46 The Aggregate Demand for Wheat The demand for US wheat is prised of two ponents: Domestic demand Export demand Total demand for wheat can be obtained by aggregating these two demands 169。 2020 Pearson Education, Inc. Chapter 4 47 The Aggregate Demand for Wheat The domestic demand for wheat is given by the equation: QDD = 1465 88P The export demand for wheat is given by the equation: QDE = 1344 138P 169。 2020 Pearson Education, Inc. Chapter 4 48 The Aggregate Demand for Wheat Domestic demand is relatively price inelastic (Ed = ) Export demand is more price elastic (Ed = ) Poorer countries that import US wheat turn to other grains and food if wheat prices increase 169。 2020 Pearson Education, Inc. Chapter 4 49 C D Export Demand Total world demand is the horizontal sum of the domestic demand AB and export demand CD. F Total Demand A B Domestic Demand E The Aggregate Demand for Wheat Wheat Price 0 10 16 18 Above C, export demand is zero, so domestic demand = total demand = AE segment 169。 2020 Pearson Education, Inc. Chapter 4 50 Consumer Surplus Consumers buy goods because it makes them better off Consumer Surplus measures how much better off they are 169。 2020 Pearson Education, Inc. Chapter 4 51 Consumer Surplus Consumer Surplus The difference between the maximum amount a consumer is willing to pay for a good and the amount actually paid Can calculate consumer surplus from the demand curve 169。 2020 Pearson Education, Inc. Chapter 4 52 Consumer Surplus Example Student wants to buy concert tickets Demand curve tells us willingness to pay for each concert ticket 1st ticket worth $20 but price is $14 so student generates $6 worth of surplus Can measure this for each ticket Total surplus is addition of surplus for each ticket purchased 169。 2020 Pearson Education, Inc. Chapter 4 53 The consumer surplus of purchasing 6 concert tickets is the sum of the surplus derived from each one individually. Consumer Surplus 6 + 5 + 4 + 3 + 2 + 1 = 21 Consumer Surplus Example Rock Concert Tickets Price ($ per ticket) 2 3 4 5 6 13 0 1 14 15 16 17 18 19 20 Market Price Will not buy more than 7 because surplus is negative 169。 2020 Pearson Education, Inc. Chapter 4 54 Consumer Surplus The stepladder demand curve can be converted into a straightline demand curve by making the units of the good smaller Consumer surplus is the area under the demand curve and above the price 169。 2020 Pearson Education, Inc. Chapter 4 55 Demand Curve Consumer Surplus Consumer Surplus for the Market Demand Consumer Surplus Rock Concert Tickets Price ($ per ticket) 2 3 4 5 6 13 0 1 Actual Expenditure 14 15 16 17 18 19 20 Market Price CS = 189。 ($20 $14)*(1600) = $19,500 169。 2020 Pearson Education, Inc. Chapter 4 56 Applying Consumer Surplus  Combining consumer surplus with the aggregate profits that producers obtain, we can evaluate: 1. Costs and benefits of different market structures 2. Public policies that alter the behavior of consumers and firms 169。 2020 Pearson Education, Inc. Chapter 4 57 Applying Consumer Surplus – An Example The Value of Clean Air Air is free in the sense that we don’t pay to breathe it The Clean Air Act was amended in 1970 Question: Were the benefits of cleaning up the air worth the costs? 169。 2020 Pearson Education, Inc. Chapter 4 58 The Value of Clean Air Empirical data determined estimates for the demand for clean air No market exists for clean air, but can see people are willing to pay for it Ex: People pay more to buy houses where the air is clean 169。 2020 Pearson Education, Inc. Chapter 4 59 The Value of Cleaner Air Using these empirical estimates, we can measure people’s consumer surplus for pollution reduction from the demand curve 169。 2020 Pearson Education, Inc. Chapter 4 60 The shaded area represents the consumer surplus generated when air pollution is reduced by 5 parts per 100 million of nitrous oxide at a cost of $1000 per part reduced. Valuing Cleaner Air 2020 10 0 1000 5 A NOX (pphm) Pollution Reduction Value 169。 2020 Pearson Education, Inc. Chapter 4 61 Value of Cleaner Air A full costbenefit analysis would include total benefit of cleanup Total benefits would be pared to total costs to determine if the clean up was worthwhile 169。 2020 Pearson Education, Inc. Chapter 4 62 Network Externalities Up to this point we have assumed that people’s demands for a good are independent of one another For some goods, one person’s demand also depends on the demands of other people 169。 2020 Pearson Education, Inc. Chapter 4 63 Network Externalities If this is the case, a work externality exists Network externalities can be positive or negative 169。 2020 Pearson Education, Inc. Chapter 4 64 Network Externalities A positive work externality exists if the quantity of a good demanded by a consumer increases in response to an increase in purchases by other consumers Negative work externalities are just the opposite 169。 2020 Pearson Education, Inc. Chapter 4 65 Network Externalities The Bandwagon Effect This is the desire to be in style, to have a good because almost everyone else has it, or to indulge in a fad This is the major objective of marketing and advertising campaigns (. toys, clothing) Positive work externality in which a consumer wishes to possess a good in pa。