大学宏观经济学第三版英文答案chapter 33Word文件下载.docx

大学宏观经济学第三版英文答案chapter 33Word文件下载.docx

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SOLUTIONSTOTEXTPROBLEMS:

QuickQuizzes

1.Threekeyfactsabouteconomicfluctuationsare:

（1）economicfluctuationsareirregularandunpredictable;

（2）mostmacroeconomicquantitiesfluctuatetogether;

and（3）asoutputfalls,unemploymentrises.

Economicfluctuationsareirregularandunpredictable,asyoucanseebylookingatagraphofrealGDPovertime.Somerecessionsareclosetogetherandothersarefarapart.Thereappearstobenorecurringpattern.

Mostmacroeconomicquantitiesfluctuatetogether.Inrecessions,realGDP,consumerspending,investmentspending,corporateprofits,andothermacroeconomicvariablesdeclineorgrowmuchmoreslowlythanduringeconomicexpansions.However,thevariablesfluctuatebydifferentamountsoverthebusinesscycle,withinvestmentvaryingmuchmorethanothervariables.

Asoutputfalls,unemploymentrises,becausewhenfirmswanttoproduceless,theydosobylayingoffworkers,thuscausingariseinunemployment.

2.Theeconomy’sbehaviorintheshortrundiffersfromitsbehaviorinthelongrunbecausetheassumptionofmonetaryneutralityappliestothelongrun,nottheshortrun.Intheshortrun,realandnominalvariablesarehighlyintertwined.

Figure1showsthemodelofaggregatedemandandaggregatesupply.Thehorizontalaxisshowsthequantityofoutputandtheverticalaxisshowsthepricelevel.

Figure1

3.Theaggregate-demandcurveslopesdownwardforthreereasons.First,whenpricesfall,thevalueofdollarsinpeople’swalletsandbankaccountsrises,sotheyarewealthier.Asaresult,theyspendmore,soaggregatedemandincreases.Second,whenpricesfall,peopleneedlessmoneytomaketheirpurchases,sotheylendmoreout,whichreducestheinterestrate.Thelowerinterestrateencouragesbusinessestoinvestmore,raisingaggregatedemand.Third,sincelowerpricesleadtoalowerinterestrate,investorsmovemoneyfromdomesticinvestmenttoforeigninvestment,supplyingdollarstotheforeign-exchangemarket,thuscausingthedollartodepreciate.Thedeclineintherealexchangeratecausesnetexportstoincrease,whichraisesaggregatedemand.

Anyeventthataltersthelevelofconsumption,investment,governmentpurchases,ornetexportsatanypricelevelwillleadtoashiftinaggregatedemand.Anincreaseinexpenditurewillshifttheaggregatedemandcurvetotheright,whileadeclineinexpenditurewillshifttheaggregatedemandcurvetotheleft.

4.Thelong-runaggregate-supplycurveisverticalbecausethepriceleveldoesnotaffectthelong-rundeterminantsofrealGDP,whichincludesuppliesoflabor,capital,naturalresources,andthelevelofavailabletechnology.Thisisjustanapplicationoftheclassicaldichotomyandmonetaryneutrality.

Therearethreereasonswhytheshort-runaggregate-supplycurveslopesupward.First,thesticky-wagetheorysuggeststhatbecausenominalwagesareslowtoadjust,adeclineinthepricelevelmeansrealwagesarehigher,sofirmshirefewerworkersandproduceless,causingaggregatesupplytodecline.Second,thesticky-pricetheorysuggeststhatthepricesofsomegoodsandservicesareslowtochange.Then,ifsomeeconomiceventcausestheoverallpriceleveltodecline,pricesthatarestickywon’tbeabletoadjustimmediately,sorelativepricesofthosegoodswillriseandthedemandforthosegoodswilldecline,leadingfirmstocutbackonproduction.Thus,loweroverallpricesleadtoloweraggregatesupply.Third,themisperceptionstheorysuggeststhatchangesintheoverallpricelevelcantemporarilymisleadsuppliers.Whenthepricelevelfallsbelowthelevelthatwasexpected,suppliersthinkthattherelativepricesoftheirproductshavedeclined,sotheyproduceless.Thus,alowerpricelevelreducesaggregatesupply.

Figure2

5.Whenapopularpresidentialcandidateiselected,causingpeopletobemoreconfidentaboutthefuture,theywillspendmore,causingtheaggregate-demandcurvetoshifttotheright,asshowninFigure2.TheeconomybeginsatpointAwithaggregate-demandcurveAD1andshort-runaggregate-supplycurveAS1.TheequilibriumhaspricelevelP1andoutputlevelY1.Increasedconfidenceaboutthefuturecausestheaggregate-demandcurvetoshifttoAD2.NowtheeconomyisatpointB,withpricelevelP2andoutputlevelY2.Overtime,theshort-runaggregate-supplycurveshiftsuptoAS2andtheeconomygetstoequilibriumatpointC,withpricelevelP3andoutputlevelY1.

QuestionsforReview

1.TwomacroeconomicvariablesthatdeclinewhentheeconomygoesintoarecessionarerealGDPandinvestmentspending（manyotheranswersarepossible）.Amacroeconomicvariablethatrisesduringarecessionistheunemploymentrate.

2.Figure3showsaggregatedemand,short-runaggregatesupply,andlong-runaggregatesupply.

Figure3

3.Theaggregate-demandcurveisdownwardslopingbecause:

（1）adecreaseinthepricelevelmakesconsumersfeelwealthier,whichinturnencouragesthemtospendmore,sothereisalargerquantityofgoodsandservicesdemanded;

（2）alowerpricelevelreducestheinterestrate,encouraginggreaterspendingoninvestment,sothereisalargerquantityofgoodsandservicesdemanded;

（3）afallintheU.S.pricelevelcausesU.S.interestratestofall,sotherealexchangeratedepreciates,stimulatingU.S.netexports,sothereisalargerquantityofgoodsandservicesdemanded.

4.Thelong-runaggregatesupplycurveisverticalbecauseinthelongrun,aneconomy'

ssupplyofgoodsandservicesdependsonitssuppliesofcapital,labor,andnaturalresourcesandontheavailableproductiontechnologyusedtoturntheseresourcesintogoodsandservices.Thepriceleveldoesnotaffecttheselong-rundeterminantsofrealGDP.

5.Threetheoriesexplainwhytheshort-runaggregate-supplycurveisupwardsloping:

（1）thesticky-wagetheory,inwhichalowerpricelevelmakesemploymentandproductionlessprofitablebecausewagesdonotadjustimmediatelytothepricelevel,sofirmsreducethequantityofgoodsandservicessupplied;

（2）thesticky-pricetheory,inwhichanunexpectedfallinthepricelevelleavessomefirmswithhigher-than-desiredpricesbecausenotallpricesadjustinstantlytochangingconditions,whichdepressessalesandinducesfirmstoreducethequantityofgoodsandservicestheyproduce;

and（3）themisperceptionstheory,inwhichalowerpricelevelcausesmisperceptionsaboutrelativeprices,andthesemisperceptionsinducesupplierstorespondtothelowerpricelevelbydecreasingthequantityofgoodsandservicessupplied.

6.Theaggregate-demandcurvemightshifttotheleftwhensomething（otherthanariseinthepricelevel）causesareductioninconsumptionspending（suchasadesireforincreasedsaving）,areductionininvestmentspending（suchasincreasedtaxesonthereturnstoinvestment）,decreasedgovernmentspending（suchasacutbackindefensespending）,orreducednetexports（suchaswhenforeigneconomiesgointorecession,soourexportsfall.

Figure4tracesthroughthestepsofsuchashiftinaggregatedemand.Theeconomybeginsinequilibrium,withshort-runaggregatesupply,AS1,intersectingaggregatedemand,AD1,atpointA.Whentheaggregate-demandcurveshiftstothelefttoAD2,theeconomymovesfrompointAtopointB,reducingthepricelevelandthequantityofoutput.Overtime,peopleadjusttheirperceptions,wages,andprices,shiftingtheshort-runaggregate-supplycurvedowntoAS2,andmovingtheeconomyfrompointBtopointC,whichisbackonthelong-runaggregatesupplycurveandhasalowerpricelevel.

Figure4

7

.Theaggregate-supplycurvemightshifttotheleftbecauseofadeclineintheeconomy'

scapitalstock,laborsupply,orproductivity,oranincreaseinthenaturalrateofunemployment,allofwhichshiftboththelong-runandshort-runaggregatesupplycurvestotheleft.Anincreaseintheexpectedpricelevelshiftsjusttheshort-runaggregate-supplycurve（notthelong-runaggregate-supplycurve）totheleft.

Figure5tracesthroughtheeffectsofsuchashift.TheeconomystartsinequilibriumatpointA.Theaggregate-supplycurvethenshiftstotheleftfromAS1toAS2.ThenewequilibriumisatpointB,theintersectionoftheaggregate-demandcurveandAS2.Astimegoeson,theeconomyreturnstolong-runequilibriumatpointA,astheshort-runaggregatesupplycurveshiftsbacktoitsoriginalposition.

Figure5

ProblemsandApplications

1.Investmentismorevariablethanconsumerspendingoverthebusinesscyclebecausefirmscancurtailinvestmentspendingmoreeasilythanhouseholdscancurtailconsumptionspending.Inrecessions,firmsknowtheywillnotbeabletosellasmanygoods,sotheywanttoproducelessandthereforetheyputoffbuyingcapital（theydonotexpandfactoriesorbuynewequipment）.Muchofconsumerspendingisonnecessities,likefood,whichcannotdeclineasmuchinrecessions.So,investmentspendingismorevariableoverthebusinesscyclethanconsumerspending.Forsimilarreasons,durablegoodsspendingisthemostvolatilesectorofconsumerspending.Durablegoods,suchasfurnitureandcarpurchases,aremorevolatileoverthebusinesscyclethannondurablegoods,suchasfoodandclothing,orservices,suchashaircutsandmedicalcare,forthesamereason.Peopleputoffbuyingdurablegoodsandjustmakedowitholdercarsandfurniturewheneconomictimesarebad.

2.a.ThecurrentstateoftheeconomyisshowninFigure6.Theaggregate-demandcurveandshort-runaggregate-supplycurveintersectatapointtotheleftoflong-runaggregatesupply.

b.Astockmarketcrashleadstoaleftward