princ-ch04-presentation6e 微观经济学 mankiw_6版Micro部分完整PPT(全英文).ppt

N GregoryMankiw Inthischapter lookfortheanswerstothesequestions Whatfactorsaffectbuyers demandforgoods Whatfactorsaffectsellers supplyofgoods Howdosupplyanddemanddeterminethepriceofagoodandthequantitysold Howdochangesinthefactorsthataffectdemandorsupplyaffectthemarketpriceandquantityofagood Howdomarketsallocateresources MarketsandCompetition Amarketisagroupofbuyersandsellersofaparticularproduct Acompetitivemarketisonewithmanybuyersandsellers eachhasanegligibleeffectonprice Inaperfectlycompetitivemarket AllgoodsexactlythesameBuyers sellerssonumerousthatnoonecanaffectmarketprice eachisa pricetaker Inthischapter weassumemarketsareperfectlycompetitive 0 Demand Thequantitydemandedofanygoodistheamountofthegoodthatbuyersarewillingandabletopurchase Lawofdemand theclaimthatthequantitydemandedofagoodfallswhenthepriceofthegoodrises otherthingsequal 0 TheDemandSchedule Demandschedule atablethatshowstherelationshipbetweenthepriceofagoodandthequantitydemandedExample Helen sdemandforlattes NoticethatHelen spreferencesobeythelawofdemand 0 Helen sDemandSchedule Curve 0 MarketDemandversusIndividualDemand Thequantitydemandedinthemarketisthesumofthequantitiesdemandedbyallbuyersateachprice SupposeHelenandKenaretheonlytwobuyersintheLattemarket Qd quantitydemanded MarketQd 0 P Q TheMarketDemandCurveforLattes 0 DemandCurveShifters Thedemandcurveshowshowpriceaffectsquantitydemanded otherthingsbeingequal These otherthings arenon pricedeterminantsofdemand i e thingsthatdeterminebuyers demandforagood otherthanthegood sprice ChangesinthemshifttheDcurve 0 DemandCurveShifters ofBuyers Increasein ofbuyersincreasesquantitydemandedateachprice shiftsDcurvetotheright 0 Supposethenumberofbuyersincreases Then ateachP Qdwillincrease by5inthisexample 0 DemandCurveShifters ofBuyers DemandCurveShifters Income Demandforanormalgoodispositivelyrelatedtoincome Increaseinincomecausesincreaseinquantitydemandedateachprice shiftsDcurvetotheright Demandforaninferiorgoodisnegativelyrelatedtoincome AnincreaseinincomeshiftsDcurvesforinferiorgoodstotheleft 0 Twogoodsaresubstitutesifanincreaseinthepriceofonecausesanincreaseindemandfortheother Example pizzaandhamburgers Anincreaseinthepriceofpizzaincreasesdemandforhamburgers shiftinghamburgerdemandcurvetotheright Otherexamples CokeandPepsi laptopsanddesktopcomputers CDsandmusicdownloads DemandCurveShifters PricesofRelatedGoods 0 Twogoodsarecomplementsifanincreaseinthepriceofonecausesafallindemandfortheother Example computersandsoftware Ifpriceofcomputersrises peoplebuyfewercomputers andthereforelesssoftware Softwaredemandcurveshiftsleft Otherexamples collegetuitionandtextbooks bagelsandcreamcheese eggsandbacon DemandCurveShifters PricesofRelatedGoods 0 DemandCurveShifters Tastes AnythingthatcausesashiftintastestowardagoodwillincreasedemandforthatgoodandshiftitsDcurvetotheright Example TheAtkinsdietbecamepopularinthe 90s causedanincreaseindemandforeggs shiftedtheeggdemandcurvetotheright 0 DemandCurveShifters Expectations Expectationsaffectconsumers buyingdecisions Examples Ifpeopleexpecttheirincomestorise theirdemandformealsatexpensiverestaurantsmayincreasenow Iftheeconomysoursandpeopleworryabouttheirfuturejobsecurity demandfornewautosmayfallnow 0 Summary VariablesThatInfluenceBuyers VariableAchangeinthisvariable Price causesamovementalongtheDcurve ofbuyers shiftstheDcurveIncome shiftstheDcurvePriceofrelatedgoods shiftstheDcurveTastes shiftstheDcurveExpectations shiftstheDcurve 0 ACTIVELEARNING1DemandCurve 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse A ThepriceofiPodsfallsB ThepriceofmusicdownloadsfallsC ThepriceofCDsfalls Drawademandcurveformusicdownloads Whathappenstoitineachofthefollowingscenarios Why MusicdownloadsandiPodsarecomplements AfallinpriceofiPodsshiftsthedemandcurveformusicdownloadstotheright ACTIVELEARNING1A PriceofiPodsfalls 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse TheDcurvedoesnotshift MovedownalongcurvetoapointwithlowerP higherQ Priceofmusicdown loads Quantityofmusicdownloads D1 P1 Q1 ACTIVELEARNING1B Priceofmusicdownloadsfalls 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse CDsandmusicdownloadsaresubstitutes AfallinpriceofCDsshiftsdemandformusicdownloadstotheleft Priceofmusicdown loads Quantityofmusicdownloads ACTIVELEARNING1C PriceofCDsfalls 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse Supply Thequantitysuppliedofanygoodistheamountthatsellersarewillingandabletosell Lawofsupply theclaimthatthequantitysuppliedofagoodriseswhenthepriceofthegoodrises otherthingsequal 0 Supplyschedule Atablethatshowstherelationshipbetweenthepriceofagoodandthequantitysupplied Example Starbucks supplyoflattes TheSupplySchedule NoticethatStarbucks supplyscheduleobeysthelawofsupply 0 Starbucks SupplySchedule Curve P Q 0 MarketSupplyversusIndividualSupply Thequantitysuppliedinthemarketisthesumofthequantitiessuppliedbyallsellersateachprice SupposeStarbucksandJittersaretheonlytwosellersinthismarket Qs quantitysupplied MarketQs 0 0 TheMarketSupplyCurve SupplyCurveShifters Thesupplycurveshowshowpriceaffectsquantitysupplied otherthingsbeingequal These otherthings arenon pricedeterminantsofsupply ChangesinthemshifttheScurve 0 SupplyCurveShifters InputPrices Examplesofinputprices wages pricesofrawmaterials Afallininputpricesmakesproductionmoreprofitableateachoutputprice sofirmssupplyalargerquantityateachprice andtheScurveshiftstotheright 0 Supposethepriceofmilkfalls Ateachprice thequantityoflattessuppliedwillincrease by5inthisexample 0 SupplyCurveShifters InputPrices SupplyCurveShifters Technology Technologydetermineshowmuchinputsarerequiredtoproduceaunitofoutput Acost savingtechnologicalimprovementhasthesameeffectasafallininputprices shiftsScurvetotheright 0 SupplyCurveShifters ofSellers Anincreaseinthenumberofsellersincreasesthequantitysuppliedateachprice shiftsScurvetotheright 0 SupplyCurveShifters Expectations Example EventsintheMiddleEastleadtoexpectationsofhigheroilprices Inresponse ownersofTexasoilfieldsreducesupplynow savesomeinventorytoselllateratthehigherprice Scurveshiftsleft Ingeneral sellersmayadjustsupply whentheirexpectationsoffuturepriceschange Ifgoodnotperishable 0 VariableAchangeinthisvariable Summary VariablesthatInfluenceSellers Price causesamovementalongtheScurveInputPrices shiftstheScurveTechnology shiftstheScurve ofSellers shiftstheScurveExpectations shiftstheScurve 0 Drawasupplycurvefortaxreturnpreparationsoftware Whathappenstoitineachofthefollowingscenarios A Retailerscutthepriceofthesoftware B Atechnologicaladvanceallowsthesoftwaretobeproducedatlowercost C Professionaltaxreturnpreparersraisethepriceoftheservicestheyprovide 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse ACTIVELEARNING2SupplyCurve Scurvedoesnotshift MovedownalongthecurvetoalowerPandlowerQ 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse ACTIVELEARNING2A Fallinpriceoftaxreturnsoftware Scurveshiftstotheright ateachprice Qincreases Priceoftaxreturnsoftware Quantityoftaxreturnsoftware S1 P1 Q1 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse ACTIVELEARNING2B Fallincostofproducingthesoftware Thisshiftsthedemandcurvefortaxpreparationsoftware notthesupplycurve 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse ACTIVELEARNING2C Professionalpreparersraisetheirprice SupplyandDemandTogether Equilibrium Phasreachedthelevelwherequantitysuppliedequalsquantitydemanded 0 Equilibriumprice thepricethatequatesquantitysuppliedwithquantitydemanded 0 Equilibriumquantity thequantitysuppliedandquantitydemandedattheequilibriumprice 0 Surplus a k a excesssupply whenquantitysuppliedisgreaterthanquantitydemanded Surplus Example IfP 5 thenQD 9lattes andQS 25lattes resultinginasurplusof16lattes 0 Surplus a k a excesssupply whenquantitysuppliedisgreaterthanquantitydemanded Facingasurplus sellerstrytoincreasesalesbycuttingprice ThiscausesQDtorise whichreducesthesurplus andQStofall 0 Surplus a k a excesssupply whenquantitysuppliedisgreaterthanquantitydemanded Facingasurplus sellerstrytoincreasesalesbycuttingprice ThiscausesQDtoriseandQStofall Surplus Pricescontinuetofalluntilmarketreachesequilibrium 0 Shortage a k a excessdemand whenquantitydemandedisgreaterthanquantitysupplied Example IfP 1 thenQD 21lattes andQS 5lattes resultinginashortageof16lattes Shortage 0 Shortage a k a excessdemand whenquantitydemandedisgreaterthanquantitysupplied Facingashortage sellersraisetheprice causingQDtofall whichreducestheshortage andQStorise 0 Shortage a k a excessdemand whenquantitydemandedisgreaterthanquantitysupplied Facingashortage sellersraisetheprice causingQDtofall andQStorise Shortage Pricescontinuetoriseuntilmarketreachesequilibrium 0 ThreeStepstoAnalyzingChangesinEq m Todeterminetheeffectsofanyevent 1 DecidewhethereventshiftsScurve Dcurve orboth 2 Decideinwhichdirectioncurveshifts 3 Usesupply demanddiagramtoseehowtheshiftchangeseq mPandQ EXAMPLE TheMarketforHybridCars STEP1 Dcurveshiftsbecausepriceofgasaffectsdemandforhybrids Scurvedoesnotshift becausepriceofgasdoesnotaffectcostofproducinghybrids STEP2 Dshiftsrightbecausehighgaspricemakeshybridsmoreattractiverelativetoothercars EXAMPLE1 AShiftinDemand EVENTTOBEANALYZED Increaseinpriceofgas STEP3 Theshiftcausesanincreaseinpriceandquantityofhybridcars EXAMPLE1 AShiftinDemand P2 Q2 Notice WhenPrises producerssupplyalargerquantityofhybrids eventhoughtheScurvehasnotshifted Alwaysbecarefultodistinguishb washiftinacurveandamovementalongthecurve TermsforShiftvs MovementAlongCurve Changeinsupply ashiftintheScurveoccurswhenanon pricedeterminantofsupplychanges liketechnologyorcosts Changeinthequantitysupplied amovementalongafixedScurveoccurswhenPchangesChangeindemand ashiftintheDcurveoccurswhenanon pricedeterminantofdemandchanges likeincomeor ofbuyers Changeinthequantitydemanded amovementalongafixedDcurveoccurswhenPchanges STEP1 Scurveshiftsbecauseeventaffectscostofproduction Dcurvedoesnotshift becauseproductiontechnologyisnotoneofthefactorsthataffectdemand STEP2 Sshiftsrightbecauseeventreducescost makesproductionmoreprofitableatanygivenprice EXAMPLE2 AShiftinSupply EVENT Newtechnologyreducescostofproducinghybridcars STEP3 Theshiftcausespricetofallandquantitytorise EXAMPLE3 AShiftinBothSupplyandDemand EVENTS PriceofgasrisesANDnewtechnologyreducesproductioncosts STEP1 Bothcurvesshift STEP2 Bothshifttotheright STEP3 Qrises buteffectonPisambiguous Ifdemandincreasesmorethansupply Prises EXAMPLE3 AShiftinBothSupplyandDemand STEP3 cont EVENTS priceofgasrisesANDnewtechnologyreducesproductioncosts Butifsupplyincreasesmorethandemand Pfalls Usethethree stepmethodtoanalyzetheeffectsofeacheventontheequilibriumpriceandquantityofmusicdownloads EventA AfallinthepriceofCDsEventB Sellersofmusicdownloadsnegotiateareductionintheroyaltiestheymustpayforeachsongtheysell EventC EventsAandBbothoccur ACTIVELEARNING3Shiftsinsupplyanddemand 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse 2 Dshiftsleft Themarketformusicdownloads 1 Dcurveshifts 3 PandQbothfall STEPS 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse ACTIVELEARNING3A FallinpriceofCDs Themarketformusicdownloads 1 Scurveshifts 2 Sshiftsright 3 Pfalls Qrises STEPS Royaltiesarepartofsellers costs 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse ACTIVELEARNING3B Fallincostofroyalties STEPS1 Bothcurvesshift seepartsA B 2 Dshiftsleft Sshiftsright 3 Punambiguouslyfalls EffectonQisambiguous ThefallindemandreducesQ theincreaseinsupplyincreasesQ 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse ACTIVELEARNING3C FallinpriceofCDsandfallincostofroyalties CONCLUSION HowPricesAllocateResources OneoftheTenPrinciplesfromChapter1 Marketsareusuallyagoodwaytoorganizeeconomicactivity Inmarketeconomies pricesadjusttobalancesupplyanddemand Theseequilibriumpricesarethesignalsthatguideeconomicdecisionsandtherebyallocatescarceresources SUMMARY Acompetitivemarkethasmanybuyersandsellers eachofwhomhaslittleornoinfluenceonthemarketprice Economistsusethesupplyanddemandmodeltoanalyzecompetitivemarkets Thedownward slopingdemandcurvereflectsthelawofdemand whichstatesthatthequantitybuyersdemandofagooddependsnegativelyonthegood sprice 2012CengageLearning AllRightsReserved Maynotbecopied scanned orduplicated inwholeorinpart exceptforuseaspermittedinalicensedistributedwithacertainproductorserviceorotherwiseonapassword protectedwebsiteforclassroomuse SUMMARY Besidesprice demanddependsonbuyers incomes tastes expectati