微观经济学教学课件：Ch03 Demand and Supply

DemandandSupplyCHAPTER3DemandandSupplyCHAPTER3AfterstudyingthischapteryouwillbeabletoDescribeacompetitivemarketandthinkaboutapriceasanopportunitycostExplaintheinfluencesondemandExplaintheinfluencesonsupplyExplainhowdemandandsupplydeterminepricesandquantitiesboughtandsoldUsedemandandsupplytomakepredictionsaboutchangesinpricesandquantitiesAfterstudyingthischapteryo2Slide,Rocket,andRollerCoasterSomepricesslide,somerocket,andsomerollercoaster.Thischapterexplainshowmarketsdeterminepricesandwhysomepricesslide,somerocket,andsomerollercoaster.Slide,Rocket,andRollerCoasMarketsandPricesAmarketisanyarrangementthatenablesbuyersandsellerstogetinformationanddobusinesswitheachother.Acompetitivemarketisamarketthathasmanybuyersandmanysellerssonosinglebuyerorsellercaninfluencetheprice.Themoneypriceofagoodistheamountofmoneyneededtobuyit.Therelativepriceofagood—theratioofitsmoneypricetothemoneypriceofthenextbestalternativegood—isitsopportunitycost.MarketsandPricesAmarketisDemandIfyoudemandsomething,thenyou1.Wantit,2.Canaffordit,and3.Havemadeadefiniteplantobuyit.Wantsaretheunlimiteddesiresorwishespeoplehaveforgoodsandservices.Demandreflectsadecisionaboutwhichwantstosatisfy.Thequantitydemandedofagoodorserviceistheamountthatconsumersplantobuyduringaparticulartimeperiod,andataparticularprice.DemandIfyoudemandsomething,DemandTheLawofDemandThelawofdemandstates:Otherthingsremainingthesame,thehigherthepriceofagood,thesmalleristhequantitydemanded;andthelowerthepriceofagood,thelargeristhequantitydemanded.ThelawofdemandresultsfromSubstitutioneffectIncomeeffectDemandTheLawofDemandDemandSubstitutioneffectWhentherelativeprice(opportunitycost)ofagoodorservicerises,peopleseeksubstitutesforit,sothequantitydemandedofthegoodorservicedecreases.IncomeeffectWhenthepriceofagoodorservicerisesrelativetoincome,peoplecannotaffordallthethingstheypreviouslybought,sothequantitydemandedofthegoodorservicedecreases.DemandSubstitutioneffectDemandDemandCurveandDemandScheduleThetermdemandreferstotheentirerelationshipbetweenthepriceofthegoodandquantitydemandedofthegood.Ademandcurveshowstherelationshipbetweenthequantitydemandedofagoodanditspricewhenallotherinfluencesonconsumers’plannedpurchasesremainthesame.DemandDemandCurveandDemandDemandFigure3.1showsademandcurveforenergybars.Ariseintheprice,otherthingsremainingthesame,bringsadecreaseinthequantitydemandedandamovementalongthedemandcurve.DemandFigure3.1showsademan微观经济学教学课件：Ch03DemandandSupplyDemandWillingnessand

AbilitytoPayAdemandcurveisalsoawillingness-and-ability-to-paycurve.Thesmallerthequantityavailable,thehigheristhepricethatsomeoneiswillingtopayforanotherunit.Willingnesstopaymeasuresmarginalbenefit.DemandWillingnessand

AbilityDemandAChangeinDemandWhenanyfactorthatinfluencesbuyingplansotherthanthepriceofthegoodchanges,thereisachangeindemandforthatgood.Thequantityofthegoodthatpeopleplantobuychangesateachandeveryprice,sothereisanewdemandcurve.Whendemandincreases,thedemandcurveshiftsrightward.Whendemanddecreases,thedemandcurveshiftsleftward.DemandAChangeinDemandDemandSixmainfactorsthatchangedemandareThepricesofrelatedgoodsExpectedfuturepricesIncomeExpectedfutureincomePopulationPreferencesDemandSixmainfactorsthatcDemandPricesofRelatedGoodsAsubstituteisagoodthatcanbeusedinplaceofanothergood.Acomplementisagoodthatisusedinconjunctionwithanothergood.Whenthepriceofsubstituteforanenergybarrisesorwhenthepriceofacomplementofanenergybarfalls,thedemandforenergybarsincreases.DemandPricesofRelatedGoodsDemandExpectedFuturePricesIfthepriceofagoodisexpectedtoriseinthefuture,currentdemandforethegoodincreasesandthedemandcurveshiftsrightward.IncomeWhenincomeincreases,consumersbuymoreofmostgoodsandthedemandcurveshiftsrightward.Anormalgoodisoneforwhichdemandincreasesasincomeincreases.Aninferiorgoodisagoodforwhichdemanddecreasesasincomeincreases.DemandExpectedFuturePricesDemandExpectedFutureIncomeWhenincomeisexpectedtoincreaseinthefuture,thedemandmightincreasenow.PopulationThelargerthepopulation,thegreateristhedemandforallgoods.PreferencesPeoplewiththesameincomehavedifferentdemandsiftheyhavedifferentpreferences.DemandExpectedFutureIncomeDemandFigure3.2showsanincreaseindemand.Becauseanenergybarisanormalgood,anincreaseinincomeincreasesthedemandforenergybars.DemandFigure3.2showsanincr微观经济学教学课件：Ch03DemandandSupplyDemandAChangeintheQuantityDemandedVersusaChangeinDemandFigure3.3illustratesthedistinctionbetweenachangeindemandandachangeinthequantitydemanded.DemandAChangeintheQuantityDemandAMovementalongtheDemandCurveWhenthepriceofthegoodchangesandeverythingelseremainsthesame,thequantitydemandedchangesandthereisamovementalongthedemandcurve.DemandAMovementalongtheDem微观经济学教学课件：Ch03DemandandSupplyDemandAShiftoftheDemandCurveIfthepriceremainsthesamebutoneoftheotherinfluencesonbuyers’planschanges,demandchangesandthedemandcurveshifts.DemandAShiftoftheDemandCuSupplyIfafirmsuppliesagoodorservice,thenthefirm1.Hastheresourcesandthetechnologytoproduceit,2.Canprofitfromproducingit,and3.Hasmadeadefiniteplantoproduceandsellit.Resourcesandtechnologydeterminewhatitispossibletoproduce.Supplyreflectsadecisionaboutwhichtechnologicallyfeasibleitemstoproduce.Thequantitysuppliedofagoodorserviceistheamountthatproducersplantosellduringagiventimeperiodataparticularprice.SupplyIfafirmsuppliesagooSupplyTheLawofSupplyThelawofsupplystates:Otherthingsremainingthesame,thehigherthepriceofagood,thegreateristhequantitysupplied;andthelowerthepriceofagood,thesmalleristhequantitysupplied.

Thelawofsupplyresultsfromthegeneraltendencyforthemarginalcostofproducingagoodorservicetoincreaseasthequantityproducedincreases(Chapter2,page37).Producersarewillingtosupplyagoodonlyiftheycanatleastcovertheirmarginalcostofproduction.SupplyTheLawofSupplySupplySupplyCurveandSupplyScheduleThetermsupplyreferstotheentirerelationshipbetweenthequantitysuppliedandthepriceofagood.Thesupplycurveshowstherelationshipbetweenthequantitysuppliedofagoodanditspricewhenallotherinfluencesonproducers’plannedsalesremainthesame.SupplySupplyCurveandSupplySupplyFigure3.4showsasupplycurveofenergybars.Ariseinthepriceofanenergybar,otherthingsremainingthesame,bringsanincreaseinthequantitysupplied.SupplyFigure3.4showsasuppl微观经济学教学课件：Ch03DemandandSupplySupplyMinimumSupplyPriceAsupplycurveisalsoaminimum-supply-pricecurve.Asthequantityproducedincreases,marginalcostincreases.Thelowestpriceatwhichsomeoneiswillingtosellanadditionalunitrises.Thislowestpriceismarginalcost.SupplyMinimumSupplyPriceSupplyAChangeinSupplyWhenanyfactorthatinfluencessellingplansotherthanthepriceofthegoodchanges,thereisachangeinsupplyofthatgood.Thequantityofthegoodthatproducersplantosellchangesateachandeveryprice,sothereisanewsupplycurve.Whensupplyincreases,thesupplycurveshiftsrightward.Whensupplydecreases,thesupplycurveshiftsleftward.SupplyAChangeinSupplySupplyThefivemainfactorsthatchangesupplyofagoodareThepricesofproductiveresourcesThepricesofrelatedgoodsproducedExpectedfuturepricesThenumberofsuppliersTechnologySupplyThefivemainfactorsthSupplyPricesofProductiveResourcesIfthepriceofresourceusedtoproduceagoodrises,theminimumpricethatasupplieriswillingtoacceptforproducingeachquantityofthatgoodrises.Soariseinthepriceofproductiveresourcesdecreasessupplyandshiftsthesupplycurveleftward.SupplyPricesofProductiveResSupplyPricesofRelatedGoodsProducedAsubstituteinproductionforagoodisanothergoodthatcanbeproducedusingthesameresources.Thesupplyofagoodincreasesifthepriceofasubstituteinproductionfalls.Goodsarecomplementsinproductioniftheymustbeproducedtogether.Thesupplyofagoodincreasesifthepriceofacomplementinproductionrises.SupplyPricesofRelatedGoodsSupplyExpectedFuturePricesIfthepriceofagoodisexpectedtoriseinthefuture,supplyofthegoodtodaydecreasesandthesupplycurveshiftsleftward.TheNumberofSuppliersThelargerthenumberofsuppliersofagood,thegreateristhesupplyofthegood.Anincreaseinthenumberofsuppliersshiftsthesupplycurverightward.SupplyExpectedFuturePricesSupplyTechnologyAdvancesintechnologycreatenewproductsandlowerthecostofproducingexistingproducts,soadvancesintechnologyincreasesupplyandshiftthesupplycurverightward.Anaturaldisasterisanegativetechnologychange,whichdecreasessupplyandshiftsthesupplycurveleftward.SupplyTechnologySupplyFigure3.5showsanincreaseinsupply.Anadvanceinthetechnologyforproducingenergybarsincreasesthesupplyofenergybarsandshiftsthesupplycurverightward.SupplyFigure3.5showsanincr微观经济学教学课件：Ch03DemandandSupplySupplyAChangeintheQuantitySuppliedVersusa

ChangeinSupplyFigure3.6illustratesthedistinctionbetweenachangeinsupplyandachangeinthequantitysupplied.SupplyAChangeintheQuantitySupplyAMovementAlongtheSupplyCurveWhenthepriceofthegoodchangesandotherinfluencesonsellers’plansremainthesame,thequantitysuppliedchangesandthereisamovementalongthesupplycurve.SupplyAMovementAlongtheSup微观经济学教学课件：Ch03DemandandSupplySupplyAShiftoftheSupplyCurveIfthepriceremainsthesamebutsomeotherinfluenceonsellers’planschanges,supplychangesandthesupplycurveshifts.SupplyAShiftoftheSupplyCuMarketEquilibriumEquilibriumisasituationinwhichopposingforcesbalanceeachother.Equilibriuminamarketoccurswhenthepricebalancestheplansofbuyersandsellers.Theequilibriumpriceisthepriceatwhichthequantitydemandedequalsthequantitysupplied.Theequilibriumquantityisthequantityboughtandsoldattheequilibriumprice.Priceregulatesbuyingandsellingplans.Priceadjustswhenplansdon’tmatch.MarketEquilibriumEquilibriumMarketEquilibriumPriceasaRegulatorFigure3.7illustratestheequilibriumpriceandequilibriumquantity.Ifthepriceis$2.00abar,thequantitysuppliedexceedsthequantitydemanded.Thereisasurplusof6millionenergybars.MarketEquilibriumPriceasaR微观经济学教学课件：Ch03DemandandSupplyMarketEquilibriumIfthepriceis$1.00abar,thequantitydemandedexceedsthequantitysupplied.Thereisashortageof9millionenergybars.Ifthepriceis$1.50abar,thequantitydemandedequalsthequantitysupplied.Thereisneitherashortagenorasurplusofenergybars.MarketEquilibriumIfthepriceMarketEquilibriumPriceAdjustmentsAtpricesabovetheequilibriumprice,asurplusforcesthepricedown.Atpricesbelowtheequilibriumprice,ashortageforcesthepriceup.Attheequilibriumprice,buyers’plansandsellers’plansagreeandthepricedoesn’tchangeuntilsomeeventchangeseitherdemandorsupply.MarketEquilibriumPriceAdjustPredictingChangesinPriceandQuantityAnIncreaseinDemandFigure3.8showsthatwhendemandincreasesthedemandcurveshiftsrightward.Attheoriginalprice,thereisnowashortage.Thepricerises,andthequantitysuppliedincreasesalongthesupplycurve.PredictingChangesinPricean微观经济学教学课件：Ch03DemandandSupplyPredictingChangesinPriceandQuantityAnIncreaseinSupplyFigure3.9showsthatwhensupplyincreasesthesupplycurveshiftsrightward.Attheoriginalprice,thereisnowasurplus.Thepricefalls,andthequantitydemandedincreasesalongthedemandcurve.PredictingChangesinPricean微观经济学教学课件：Ch03DemandandSupplyPredictingChangesinPriceandQuantityAllPossibleChangesinDemandandSupplyAchangedemandorsupplyorbothdemandandsupplychangestheequilibriumpriceandtheequilibriumquantity.PredictingChangesinPriceanPredictingChangesinPriceandQuantityChangeinDemandwithNoChangeinSupplyWhendemandincreases,equilibriumpricerisesandthe

equilibriumquantityincreases.PredictingChangesinPriceanPredictingChangesinPriceandQuantityChangeinDemandwithNoChangeinSupplyWhendemanddecreases,theequilibriumpricefallsandtheequilibriumquantitydecreases.PredictingChangesinPriceanPredictingChangesinPriceandQuantityChangeinSupplywithNoChangeinDemandWhensupplyincreases,theequilibriumpricefallsandthe

equilibriumquantityincreases.PredictingChangesinPriceanPredictingChangesinPriceandQuantityChangeinSupplywithNoChangeinDemandWhensupplydecreases,theequilibriumpricerisesandthe

equilibriumquantitydecreases.PredictingChangesinPriceanPredictingChangesinPriceandQuantityIncreaseinBothDemandandSupplyAnincreaseindemandandanincreaseinsupplyincreasetheequilibriumquantity.Thechangeinequilibriumpriceisuncertainbecausetheincreaseindemandraisestheequilibriumpriceandtheincreaseinsupplylowersit.PredictingChangesinPriceanPredictingChangesinPriceandQuantityDecreaseinBothDemandandSupplyAdecreaseinbothdemandandsupplydecreasestheequilibriumquantity.Thechangeinequilibriumpriceisuncertainbecausethedecreaseindemandlowerstheequilibriumpriceandthedecreaseinsupplyraisesit.PredictingChangesinPriceanPredictingChangesinPriceandQuantityDecreaseinDemandandIncreaseinSupplyAdecreaseindemandandanincreaseinsupplylowerstheequilibriumprice.Thechangeinequilibriumquantityisuncertainbecausethedecreaseindemanddecreasestheequilibriumquantityandtheincreaseinsupplyincreasesit.PredictingChangesinPriceanPredictingChangesinPriceandQuantityIncreaseinDemandandDecreaseinSupplyAnincreaseindemandandadecreaseinsupplyraisestheequilibriumprice.Thechangeinequilibriumquantityisuncertainbecausetheincreaseindemandincreasestheequilibriumquantityandthedecreaseinsupplydecreasesit.PredictingChangesinPricean微观经济学教学课件：Ch03DemandandSupply微观经济学教学课件：Ch03DemandandSupply微观经济学教学课件：Ch03DemandandSupply微观经济学教学课件：Ch03DemandandSupply微观经济学教学课件：Ch03DemandandSupply微观经济学教学课件：Ch03DemandandSupply微观经济学教学课件：Ch03DemandandSupply微观经济学教学课件：Ch03DemandandSupply微观经济学教学课件：Ch03DemandandSupplyTHEENDTHEENDDemandandSupplyCHAPTER3DemandandSupplyCHAPTER3AfterstudyingthischapteryouwillbeabletoDescribeacompetitivemarketandthinkaboutapriceasanopportunitycostExplaintheinfluencesondemandExplaintheinfluencesonsupplyExplainhowdemandandsupplydeterminepricesandquantitiesboughtandsoldUsedemandandsupplytomakepredictionsaboutchangesinpricesandquantitiesAfterstudyingthischapteryo70Slide,Rocket,andRollerCoasterSomepricesslide,somerocket,andsomerollercoaster.Thischapterexplainshowmarketsdeterminepricesandwhysomepricesslide,somerocket,andsomerollercoaster.Slide,Rocket,andRollerCoasMarketsandPricesAmarketisanyarrangementthatenablesbuyersandsellerstogetinformationanddobusinesswitheachother.Acompetitivemarketisamarketthathasmanybuyersandmanysellerssonosinglebuyerorsellercaninfluencetheprice.Themoneypriceofagoodistheamountofmoneyneededtobuyit.Therelativepriceofagood—theratioofitsmoneypricetothemoneypriceofthenextbestalternativegood—isitsopportunitycost.MarketsandPricesAmarketisDemandIfyoudemandsomething,thenyou1.Wantit,2.Canaffordit,and3.Havemadeadefiniteplantobuyit.Wantsaretheunlimiteddesiresorwishespeoplehaveforgoodsandservices.Demandreflectsadecisionaboutwhichwantstosatisfy.Thequantitydemandedofagoodorserviceistheamountthatconsumersplantobuyduringaparticulartimeperiod,andataparticularprice.DemandIfyoudemandsomething,DemandTheLawofDemandThelawofdemandstates:Otherthingsremainingthesame,thehigherthepriceofagood,thesmalleristhequantitydemanded;andthelowerthepriceofagood,thelargeristhequantitydemanded.ThelawofdemandresultsfromSubstitutioneffectIncomeeffectDemandTheLawofDemandDemandSubstitutioneffectWhentherelativeprice(opportunitycost)ofagoodorservicerises,peopleseeksubstitutesforit,sothequantitydemandedofthegoodorservicedecreases.IncomeeffectWhenthepriceofagoodorservicerisesrelativetoincome,peoplecannotaffordallthethingstheypreviouslybought,sothequantitydemandedofthegoodorservicedecreases.DemandSubstitutioneffectDemandDemandCurveandDemandScheduleThetermdemandreferstotheentirerelationshipbetweenthepriceofthegoodandquantitydemandedofthegood.Ademandcurveshowstherelationshipbetweenthequantitydemandedofagoodanditspricewhenallotherinfluencesonconsumers’plannedpurchasesremainthesame.DemandDemandCurveandDemandDemandFigure3.1showsademandcurveforenergybars.Ariseintheprice,otherthingsremainingthesame,bringsadecreaseinthequantitydemandedandamovementalongthedemandcurve.DemandFigure3.1showsademan微观经济学教学课件：Ch03DemandandSupplyDemandWillingnessand

AbilitytoPayAdemandcurveisalsoawillingness-and-ability-to-paycurve.Thesmallerthequantityavailable,thehigheristhepricethatsomeoneiswillingtopayforanotherunit.Willingnesstopaymeasuresmarginalbenefit.DemandWillingnessand

AbilityDemandAChangeinDemandWhenanyfactorthatinfluencesbuyingplansotherthanthepriceofthegoodchanges,thereisachangeindemandforthatgood.Thequantityofthegoodthatpeopleplantobuychangesateachandeveryprice,sothereisanewdemandcurve.Whendemandincreases,thedemandcurveshiftsrightward.Whendemanddecreases,thedemandcurveshiftsleftward.DemandAChangeinDemandDemandSixmainfactorsthatchangedemandareThepricesofrelatedgoodsExpectedfuturepricesIncomeExpectedfutureincomePopulationPreferencesDemandSixmainfactorsthatcDemandPricesofRelatedGoodsAsubstituteisagoodthatcanbeusedinplaceofanothergood.Acomplementisagoodthatisusedinconjunctionwithanothergood.Whenthepriceofsubstituteforanenergybarrisesorwhenthepriceofacomplementofanenergybarfalls,thedemandforenergybarsincreases.DemandPricesofRelatedGoodsDemandExpectedFuturePricesIfthepriceofagoodisexpectedtoriseinthefuture,currentdemandforethegoodincreasesandthedemandcurveshiftsrightward.IncomeWhenincomeincreases,consumersbuymoreofmostgoodsandthedemandcurveshiftsrightward.Anormalgoodisoneforwhichdemandincreasesasincomeincreases.Aninferiorgoodisagoodforwhichdemanddecreasesasincomeincreases.DemandExpectedFuturePricesDemandExpectedFutureIncomeWhenincomeisexpectedtoincreaseinthefuture,thedemandmightincreasenow.PopulationThelargerthepopulation,thegreateristhedemandforallgoods.PreferencesPeoplewiththesameincomehavedifferentdemandsiftheyhavedifferentpreferences.DemandExpectedFutureIncomeDemandFigure3.2showsanincreaseindemand.Becauseanenergybarisanormalgood,anincreaseinincomeincreasesthedemandforenergybars.DemandFigure3.2showsanincr微观经济学教学课件：Ch03DemandandSupplyDemandAChangeintheQuantityDemandedVersusaChangeinDemandFigure3.3illustratesthedistinctionbetweenachangeindemandandachangeinthequantitydemanded.DemandAChangeintheQuantityDemandAMovementalongtheDemandCurveWhenthepriceofthegoodchangesandeverythingelseremainsthesame,thequantitydemandedchangesandthereisamovementalongthedemandcurve.DemandAMovementalongtheDem微观经济学教学课件：Ch03DemandandSupplyDemandAShiftoftheDemandCurveIfthepriceremainsthesamebutoneoftheotherinfluencesonbuyers’planschanges,demandchangesandthedemandcurveshifts.DemandAShiftoftheDemandCuSupplyIfafirmsuppliesagoodorservice,thenthefirm1.Hastheresourcesandthetechnologytoproduceit,2.Canprofitfromproducingit,and3.Hasmadeadefiniteplantoproduceandsellit.Resourcesandtechnologydeterminewhatitispossibletoproduce.Supplyreflectsadecisionaboutwhichtechnologicallyfeasibleitemstoproduce.Thequantitysuppliedofagoodorserviceistheamountthatproducersplantosellduringagiventimeperiodataparticularprice.SupplyIfafirmsuppliesagooSupplyTheLawofSupplyThelawofsupplystates:Otherthingsremainingthesame,thehigherthepriceofagood,thegreateristhequantitysupplied;andthelowerthepriceofagood,thesmalleristhequantitysupplied.

Thelawofsupplyresultsfromthegeneraltendencyforthemarginalcostofproducingagoodorservicetoincreaseasthequantityproducedincreases(Chapter2,page37).Producersarewillingtosupplyagoodonlyiftheycanatleastcovertheirmarginalcostofproduction.SupplyTheLawofSupplySupplySupplyCurveandSupplyScheduleThetermsupplyreferstotheentirerelationshipbetweenthequantitysuppliedandthepriceofagood.Thesupplycurveshowstherelationshipbetweenthequantitysuppliedofagoodanditspricewhenallotherinfluencesonproducers’plannedsalesremainthesame.SupplySupplyCurveandSupplySupplyFigure3.4showsasupplycurveofenergybars.Ariseinthepriceofanenergybar,otherthingsremainingthesame,bringsanincreaseinthequantitysupplied.SupplyFigure3.4showsasuppl微观经济学教学课件：Ch03DemandandSupplySupplyMinimumSupplyPriceAsupplycurveisalsoaminimum-supply-pricecurve.Asthequantityproducedincreases,marginalcostincreases.Thelowestpriceatwhichsomeoneiswillingtosellanadditionalunitrises.Thislowestpriceismarginalcost.SupplyMinimumSupplyPriceSupplyAChangeinSupplyWhenanyfactorthatinfluencessellingplansotherthanthepriceofthegoodchanges,thereisachangeinsupplyofthatgood.Thequantityofthegoodthatproducersplantosellchangesateachandeveryprice,sothereisanewsupplycurve.Whensupplyincreases,thesupplycurveshiftsrightward.Whensupplydecreases,thesupplycurveshiftsleftward.SupplyAChangeinSupplySupplyThefivemainfactorsthatchangesupplyofagoodareThepricesofproductiveresourcesThepricesofrelatedgoodsproducedExpectedfuturepricesThenumberofsuppliersTechnologySupplyThefivemainfactorsthSupplyPricesofProductiveResourcesIfthepriceofresourceusedtoproduceagoodrises,theminimumpricethatasupplieriswillingtoacceptforproducingeachquantityofthatgoodrises.Soariseinthepriceofproductiveresourcesdecreasessupplyandshiftsthesupplycurveleftward.SupplyPricesofProductiveResSupplyPricesofRelatedGoodsProducedAsubstituteinproductionforagoodisanothergoodthatcanbeproducedusingthesameresources.Thesupplyofagoodincreasesifthepriceofasubstituteinproductionfalls.Goodsarecomplementsinproductioniftheymustbeproducedtogether.Thesupplyofagoodincreasesifthepriceofacomplementinproductionrises.SupplyPricesofRelatedGoodsSupplyExpectedFuturePricesIfthepriceofagoodisexpectedtoriseinthefuture,supplyofthegoodtodaydecreasesandthesupplycurveshiftsleftward.TheNumberofSuppliersThelargerthenumberofsuppliersofagood,thegreateristhesupplyofthegood.Anincreaseinthenumberofsuppliersshiftsthesupplycurverightward.SupplyExpectedFuturePricesSupplyTechnologyAdvancesintechnologycreatenewproductsandlowerthecostofproducingexistingproducts,soadvancesintechnologyincreasesupplyandshiftthesupplycurverightward.Anaturaldisasterisanegativetechnologychange,whichdecreasessupplyandshiftsthesupplycurveleftward.SupplyTechnologySupplyFigure3.5showsanincreaseinsupply.Anadvanceinthetechnologyforproducingenergybarsincreasesthesupplyofenergybarsandshiftsthesupplycurverightward.SupplyFigure3.5showsanincr微观经济学教学课件：Ch03DemandandSupplySupplyAChangeintheQuantitySuppliedVersusa

ChangeinSupplyFigure3.6illustratesthedistinctionbetweenachangeinsupplyandachangeinthequantitysupplied.SupplyAChangeintheQuantitySupplyAMovementAlongtheSupplyCurveWhenthepriceofthegoodchangesandotherinfluencesonsellers’plansremainthesame,thequantitysuppliedchangesandthereisamovementalongthesupplycurve.SupplyAMovementAlongtheSup微观经济学教学课件：Ch03DemandandSupplySupplyAShiftoftheSupplyCurveIfthepriceremainsthesamebutsomeotherinfluenceonsellers’planschanges,supplychangesandthesupplycurveshifts.SupplyAShiftoftheSupplyCuMarketEquilibriumEquilibriumisasituationinwhichopposingforcesbalanceeachother.Equilibriuminamarketoccurswhenthepricebalancestheplansofbuyersandsellers.Theequilibriumpriceisthepriceatwhichthequantitydemandedequalsthequantitysupplied.Theequilibriumquantityisthequantityboughtandsoldattheequilibriumprice.Priceregulatesbuyingandsellingplans.Priceadjustswhenplansdon’tmatch.MarketEquilibriumEquilibriumMarketEquilibriumPriceasaRegulatorFigure3.7illustratestheequilibriumpriceandequilibriumquan