克鲁格曼国际经济学第八版上册课后答案-3

Chapter3LaborProductivityandComparativeAdvantage:TheRicardianModelChapterOrganizationTheConceptofComparativeAdvantageAOne-FactorEconomyProductionPossibilitiesRelativePricesandSupplyTradeinaOne-FactorWorldBox:ComparativeAdvantageinPractice:TheCaseofBabeRuthDeterminingtheRelativePriceafterTradeTheGainsfromTradeANumericalExampleBox:TheLossesfromNon-TradeRelativeWagesMisconceptionsaboutComparativeAdvantageProductivityandCompetitivenessThePauperLaborArgumentExploitationBox:DoWagesReflectProductivity?ComparativeAdvantagewithManyGoodsSettingUptheModelRelativeWagesandSpecializationDeterminingtheRelativeWagewithaMultigoodModelAddingTransportCostsandNon-TradedGoodsEmpiricalEvidenceontheRicardianModelSummaryChapter3LaborProductivityandComparativeAdvantage:TheRicardianModel9ChapterOverviewTheRicardianmodelprovidesanintroductiontointernationaltradetheory.Thismostbasicmodeloftradeinvolvestwocountries,twogoods,andonefactorofproduction,labor.Differencesinrelativelaborproductivityacrosscountriesgiverisetointernationaltrade.ThisRicardianmodel,simpleasitis,generatesimportantinsightsconcerningcomparativeadvantageandthegainsfromtrade.Theseinsightsarenecessaryfoundationsforthemorecomplexmodelspresentedinlaterchapters.Thetextexpositionbeginswiththeexaminationoftheproductionpossibilityfrontierandtherelativepricesofgoodsforonecountry.Theproductionpossibilityfrontierislinearbecauseoftheassumptionofconstantreturnstoscaleforlabor,thesolefactorofproduction.Theopportunitycostofonegoodintermsoftheotherequalsthepriceratiosincepricesequalcosts,costsequalunitlaborrequirementstimeswages,andwagesareequalineachindustry.Afterdefiningtheseconceptsforasinglecountry,asecondcountryisintroducedwhichhasdifferentrelativeunitlaborrequirements.Generalequilibriumrelativesupplyanddemandcurvesaredeveloped.Thisanalysisdemonstratesthatatleastonecountrywillspecializeinproduction.Thegainsfromtradearethendemonstratedwithagraphandanumericalexample.Theintuitionofindirectproduction,thatis“producing”agoodbyproducingthegoodforwhichacountryenjoysacomparativeadvantageandthentradingfortheothergood,isanappealingconcepttoemphasizewhenpresentingthegainsfromtradeargument.StudentsareabletoapplytheRicardiantheoryofcomparativeadvantagetoanalyzethreemisconceptionsabouttheadvantagesoffreetrade.Eachofthethree“myths”representsacommonargumentagainstfreetradeandtheflawsofeachcanbedemonstratedinthecontextofexamplesalreadydevelopedinthechapter.Whiletheinitialintuitionsaredevelopedinthecontextofatwogoodmodel,itisstraightforwardtoextendthemodeltodescribetradepatternswhenthereareNgoods.Thisanalysiscanbeusedtoexplainwhyasmallcountryspecializesintheproductionofafewgoodswhilealargecountryspecializesintheproductionofmanygoods.Thechapterendsbydiscussingtherolethattransportcostsplayinmakingsomegoodsnon-traded.AnswerstoTextbookProblems1.a.Theproductionpossibilitycurveisastraightlinethatinterceptstheappleaxisat400(1200/3)andthebananaaxisat600(1200/2).b.Theopportunitycostofapplesintermsofbananasis3/2.Ittakesthreeunitsoflabortoharvestanapplebutonlytwounitsoflabortoharvestabanana.Ifoneforegoesharvestinganapple,thisfreesupthreeunitsoflabor.These3unitsoflaborcouldthenbeusedtoharvest1.5bananas.c.Labormobilityensuresacommonwageineachsectorandcompetitionensuresthepriceofgoodsequalstheircostofproduction.Thus,therelativepriceequalstherelativecosts,whichequalsthewagetimestheunitlaborrequirementforapplesdividedbythewagetimestheunitlaborrequirementforbananas.Sincewagesareequalacrosssectors,thepriceratioequalstheratiooftheunitlaborrequirement,whichis3applesper2bananas.2.a.Theproductionpossibilitycurveislinear,withtheinterceptontheappleaxisequalto160(800/5)andtheinterceptonthebananaaxisequalto800(800/1).b.Theworldrelativesupplycurveisconstructedbydeterminingthesupplyofapplesrelativetothesupplyofbananasateachrelativeprice.Thelowestrelativepriceatwhichapplesareharvestedis3applesper2bananas.Therelativesupplycurveisflatatthisprice.Themaximumnumberofapplessuppliedatthepriceof3/2is400suppliedbyHomewhile,atthisprice,Foreignharvests800bananasandnoapples,givingamaximumrelativesupplyatthispriceof1/2.Thisrelative10Krugman/Obstfeld•InternationalEconomics:TheoryandPolicy,EighthEditionsupplyholdsforanypricebetween3/2and5.Atthepriceof5,bothcountrieswouldharvestapples.Therelativesupplycurveisagainflatat5.Thus,therelativesupplycurveisstepshaped,flatattheprice3/2fromtherelativesupplyof0to1/2,verticalattherelativequantity1/2risingfrom3/2to5,andthenflatagainfrom1/2toinfinity.3.a.TherelativedemandcurveincludesthePoints(1/5,5),(1/2,2),(1,1),(2,1/2).b.Theequilibriumrelativepriceofapplesisfoundattheintersectionoftherelativedemandandrelativesupplycurves.ThisisthePoint(1/2,2),wheretherelativedemandcurveintersectstheverticalsectionoftherelativesupplycurve.Thustheequilibriumrelativepriceis2.c.Homeproducesonlyapples,Foreignproducesonlybananas,andeachcountrytradessomeofitsproductfortheproductoftheothercountry.d.Intheabsenceoftrade,Homecouldgainthreebananasbyforegoingtwoapples,andForeigncouldgainbyoneappleforegoingfivebananas.Tradeallow