andMarketDemand(微观经济学-华侨大学,JeffCaldw

Chapter4IndividualandMarketDemandChapter4Slide2TopicstobeDiscussedIndividualDemandIncomeandSubstitutionEffectsMarketDemandConsumerSurplusChapter4Slide3TopicstobeDiscussedNetworkExternalitiesEmpiricalEstimationofDemandChapter4Slide4IndividualDemandPriceChangesUsingthefiguresdevelopedinthepreviouschapter,theimpactofachangeinthepriceoffoodcanbeillustratedusingindifferencecurves.Chapter4Slide5EffectofaPriceChangeFood(unitspermonth)Clothing(unitspermonth)456U2U3ABDU141220Threeseparateindifferencecurvesaretangenttoeachbudgetline.Assume:•I=$20•PC=$2•PF=$2,$1,$.5010Chapter4Slide6Price-ConsumptionCurveEffectofaPriceChangeFood(unitspermonth)Clothing(unitspermonth)456U2U3ABDU141220Theprice-consumptioncurvetracesouttheutilitymaximizingmarketbasketforthevariouspricesforfood.Chapter4Slide7EffectofaPriceChangeDemandCurveIndividualDemandrelatesthequantityofagoodthataconsumerwillbuytothepriceofthatgood.Food(unitspermonth)PriceofFoodHEG$2.0041220$1.00$.50Chapter4Slide8IndividualDemandTwoImportantPropertiesofDemandCurves1)Thelevelofutilitythatcanbeattainedchangesaswemovealongthecurve.TheIndividualDemandCurveChapter4Slide9IndividualDemandTwoImportantPropertiesofDemandCurves2)Ateverypointonthedemandcurve,theconsumerismaximizingutilitybysatisfyingtheconditionthattheMRSoffoodforclothingequalstheratioofthepricesoffoodandclothing.TheIndividualDemandCurveChapter4Slide10EffectofaPriceChangeFood(unitspermonth)PriceofFoodHEG$2.0041220$1.00$.50DemandCurve•E:Pf/Pc=2/2=1=MRS•G:Pf/Pc=1/2=.5=MRS•H:Pf/Pc=.5/2=.25=MRSWhenthepricefalls:Pf/Pc&MRSalsofallChapter4Slide11IndividualDemandIncomeChangesUsingthefiguresdevelopedinthepreviouschapter,theimpactofachangeintheincomecanbeillustratedusingindifferencecurves.Chapter4Slide12EffectsofIncomeChangesFood(unitspermonth)Clothing(unitspermonth)Anincreaseinincome,withthepricesfixed,causesconsumerstoaltertheirchoiceofmarketbasket.Income-ConsumptionCurve34AU1510BU2D716U3Assume:Pf=$1Pc=$2I=$10,$20,$30Chapter4Slide13EffectsofIncomeChangesFood(unitspermonth)PriceoffoodAnincreaseinincome,from$10to$20to$30,withthepricesfixed,shiftstheconsumer’sdemandcurvetotheright.$1.004D1E10D2G16D3HChapter4Slide14IndividualDemandIncomeChangesTheincome-consumptioncurvetracesouttheutility-maximizingcombinationsoffoodandclothingassociatedwitheveryincomelevel.Chapter4Slide15IndividualDemandIncomeChangesAnincreaseinincomeshiftsthebudgetlinetotheright,increasingconsumptionalongtheincome-consumptioncurve.Simultaneously,theincreaseinincomeshiftsthedemandcurvetotheright.Chapter4Slide16IndividualDemandIncomeChangesWhentheincome-consumptioncurvehasapositiveslope:Thequantitydemandedincreaseswithincome.Theincomeelasticityofdemandispositive.Thegoodisanormalgood.NormalGoodvs.InferiorGoodChapter4Slide17IndividualDemandIncomeChangesWhentheincome-consumptioncurvehasanegativeslope:Thequantitydemandeddecreaseswithincome.Theincomeelasticityofdemandisnegative.Thegoodisaninferiorgood.NormalGoodvs.InferiorGoodChapter4Slide18AnInferiorGoodHamburger(unitspermonth)Steak(unitspermonth)1530U3CIncome-ConsumptionCurve…buthamburgerbecomesaninferiorgoodwhentheincomeconsumptioncurvebendsbackwardbetweenBandC.10520510AU1BU2Bothhamburgerandsteakbehaveasanormalgood,betweenAandB...Chapter4Slide19IndividualDemandEngelCurvesEngelcurvesrelatethequantityofgoodconsumedtoincome.Ifthegoodisanormalgood,theEngelcurveisupwardsloping.Ifthegoodisaninferiorgood,theEngelcurveisdownwardsloping.Chapter4Slide20EngelCurvesFood(unitspermonth)30481210Income($permonth)20160Engelcurvesslopeupwardfornormalgoods.Chapter4Slide21EngelCurvesEngelcurvesslopebackwardbendingforinferiorgoods.InferiorNormalFood(unitspermonth)30481210Income($permonth)20160ConsumerExpendituresintheUnitedStatesEntertainment70094712741514205426544300OwnedDwellings1116172522533243445457939898RentedDwellings1957217023712536213715401266HealthCare1031169719181820205222142642Food2656338541094888542962208279Clothing85997813631772177826143442ExpenditureLessthan1,000-20,000-30,000-40,000-50,000-70,000-($)on:$10,00019,00029,00039,00049,00069,000andaboveIncomeGroup(1997$)Chapter4Slide23IndividualDemand1)Twogoodsareconsideredsubstitutesifanincrease(decrease)inthepriceofoneleadstoanincrease(decrease)inthequantitydemandedoftheother.e.g.movieticketsandvideorentalsSubstitutesandComplementsChapter4Slide24IndividualDemand2)Twogoodsareconsideredcomplementsifanincrease(decrease)inthepriceofoneleadstoadecrease(increase)inthequantitydemandedoftheother.e.g.gasolineandmotoroilSubstitutesandComplementsChapter4Slide25IndividualDemand3)TwogoodsareindependentwhenachangeinthepriceofonegoodhasnoeffectonthequantitydemandedoftheotherSubstitutesandComplementsChapter4Slide26IndividualDemandSubstitutesandComplementsIfthepriceconsumptioncurveisdownward-sloping,thetwogoodsareconsideredsubstitutes.Ifthepriceconsumptioncurveisupward-sloping,thetwogoodsareconsideredcomplements.Theycouldbeboth!Chapter4Slide27IncomeandSubstitutionEffectsAfallinthepriceofagoodhastwoeffects:Substitution&IncomeSubstitutionEffectConsume