曼昆经济学原理复习资料整理.

1Q4Whyshouldpolicymakersthinkaboutincentives?Policymakersneedtothinkaboutincentivessotheycanunderstandhowpeoplewillrespondtothepoliciestheyputinplace.Thetext'sexampleofseatbeltsshowsthatpolicyactionscanhavequiteunintendedconsequences.Ifincentivesmatteralot,theymayleadtoaverydifferenttypeofpolicy;forexample,someeconomistshavesuggestedputtingknivesinsteeringcolumnssothatpeoplewilldrivemuchmorecarefully!Whilethissuggestionissilly,ithighlightstheimportanceofincentives.Q6whatdoestheinvisiblehandofthemarketplacedo?The"invisiblehand"ofthemarketplacerepresentstheideathateventhoughindividualsandfirmsareallactingintheirownself-interest,pricesandthemarketplaceguidethemtodowhatisgoodforsocietyasawhole.2Q1Howiseconomicslikeascience?Economicsislikeasciencebecauseeconomistsusethescientificmethod.Theydevisetheories,collectdata,andthenanalyzethesedatainanattempttoverifyorrefutetheirtheoriesabouthowtheworldworks.Economistsusetheoryandobservationlikeotherscientists,buttheyarelimitedintheirabilitytoruncontrolledexperiments.Instead,theymustrelyonnaturalexperiments.Q5Useaproductionpossibilitiesfrontiertodescribetheideaof“efficiency”?Theideaofefficiencyisthatanoutcomeisefficientiftheeconomyisgettingallitcanfromthescarceresourcesithasavailable.Intermsoftheproductionpossibilitiesfrontier,anefficientpointisapointonthefrontier,suchaspointAinFigure4.Apointinsidethefrontier,suchaspointB,isinefficientsincemoreofonegoodcouldbeproducedwithoutreducingtheproductionofanothergood.Q7Whatisthedifferencebetweenapositiveandanormativestatement?Giveanexampleofthat.Positivestatementsaredescriptiveandmakeaclaimabouthowtheworldis,whilenormativestatementsareprescriptiveandmakeaclaimabouthowtheworldoughttobe.Hereisanexample.Positive:Arapidgrowthrateofmoneyisthecauseofinflation.Normative:Thegovernmentshouldkeepthegrowthrateofmoneylow.3Q1Explainhowabsoluteadvantageandcomparativeadvantagediffer.Absoluteadvantagereflectsacomparisonoftheproductivityofoneperson,firm,ornationtothatofanother,whilecomparativeadvantageisbasedontherelativeopportunitycostsofthepersons,firms,ornations.Whileaperson,firm,ornationmayhaveanabsoluteadvantageinproducingeverygood,theycan'thaveacomparativeadvantageineverygood.Q4WillanationtendtoexportorimportgoodstoQuestion2.Anationwillexportgoodsforwhichithasacomparativeadvantagebecauseithasasmalleropportunitycostofproducingthosegoods.Asaresult,citizensofallnationsareabletoconsumequantitiesofgoodsthatareoutsidetheirproductionpossibilitiesfrontiers.4Q5Propeye’sincomedeclines,andasaresult,hebuysmorespinach.Isspinachaninferiororanormalgoods?WhathappenstoPopeye’sdemandcurveforspinach?SincePopeyebuysmorespinachwhenhisincomefalls,spinachisaninferiorgoodforhim.Sincehebuysmorespinach,butthepriceofspinachisunchanged,hisdemandcurveforspinachshiftsoutasaresultofthedecreaseinhisincome.Q8Doseachangeinproducers’technologyleadtoamovementalongthesupplycurve?Doesachangeinpriceleadtoamovementalongthesupplycurveorashiftinthesupplycurve?Achangeinproducers'technologyleadstoashiftinthesupplycurve.Achangeinpriceleadstoamovementalongthesupplycurve.Q9Definetheequilibriumofamarket.Describetheforcesthatmoveamarkettowardsitsequilibrium.Theequilibriumofamarketisthepointatwhichthequantitydemandedisequaltoquantitysupplied.Ifthepriceisabovetheequilibriumprice,sellerswanttosellmorethanbuyerswanttobuy,sothereisasurplus.Sellerstrytoincreasetheirsalesbycuttingprices.Thatcontinuesuntiltheyreachtheequilibriumprice.Ifthepriceisbelowtheequilibriumprice,buyerswanttobuymorethansellerswanttosell,sothereisashortage.Sellerscanraisetheirpricewithoutlosingcustomers.Thatcontinuesuntiltheyreachtheequilibriumprice.Q11Describetheroleofpricesinmarketeconomies.Pricesplayavitalroleinmarketeconomiesbecausetheybringmarketsintoequilibrium.Ifthepriceisdifferentfromitsequilibriumlevel,quantitysuppliedandquantitydemandedarenotequal.Theresultingsurplusorshortageleadssupplierstoadjustthepriceuntilequilibriumisrestored.Pricesthusserveassignalsthatguideeconomicdecisionsandallocatescarceresources.5Q2Listandexplainthefourdeterminantsofthepriceelasticityofdemanddiscussedinthechapter.Thedeterminantsofthepriceelasticityofdemandincludehowavailableclosesubstitutesare,whetherthegoodisanecessityoraluxury,howbroadlydefinedthemarketis,andthetimehorizon.Luxurygoodshavegreaterpriceelastictiesthannecessities,goodswithclosesubstituteshavegreaterelasticties,goodsinmorenarrowlydefinedmarketshavegreaterelasticties,andtheelasticityofdemandishigherthelongerthetimehorizon.Q4Onasupply-and-demanddiagram,showequilibriumprice,equilibriumquantity,andthetotalrevenuereceivedbyproducers.Figure1presentsasupply-and-demanddiagram,showingequilibriumprice,equilibriumquantity,andthetotalrevenuereceivedbyproducers.Totalrevenueequalstheequilibriumpricetimestheequilibriumquantity,whichistheareaoftherectangleshowninthefigure.Figure16Q2Whichcausesashortageofagood—apriceceilingorapricefloor?Whichcausesasurplus?Ashortageofagoodariseswhenthereisabindingpriceceiling.Asurplusofagoodariseswhenthereisabindingpricefloor.Q6Howdoesataxonagoodaffectthepricepaidbybuyers,andthequantitysold?Ataxonagoodraisesthepricebuyerspay,lowersthepricesellersreceive,andreducesthequantitysold.Q7Whatdetermineshowtheburdenofataxisdividedbetweenbuyersandsellers?Why?Theburdenofataxisdividedbetweenbuyersandsellersdependingontheelasticityofdemandandsupply.Elasticityrepresentsthewillingnessofbuyersorsellerstoleavethemarket,whichinturnsdependsontheiralternatives.Whenagoodistaxed,thesideofthemarketwithfewergoodalternativescannoteasilyleavethemarketandthusbearsmoreoftheburdenofthetax.7Q1Explainhowbuyer’swillingnesstopay,consumer’surplus,andthedemandcurvearerelated.Buyers'willingnesstopay,consumersurplus,andthedemandcurveareallcloselyrelated.Theheightofthedemandcurverepresentsthewillingnesstopayofthebuyers.Consumersurplusistheareabelowthedemandcurveandabovetheprice,whichequalseachbuyer'swillingnesstopaylessthepriceofthegood.Q2Explainhowseller’scosts,producer’ssurplus,andthesupplycurvearerelated.Sellers'costs,producersurplus,andthesupplycurveareallcloselyrelated.Theheightofthesupplycurverepresentsthecostsofthesellers.Producersurplusistheareabelowthepriceandabovethesupplycurve,whichequalsthepriceminuseachsellers'costs.Figure413Q2Giveanexampleofanopportunitycostthataccountantmightnotcountasacost.Whywouldtheaccountantignorethecost?Anaccountantwouldnotcounttheowner’sopportunitycostofalternativeemploymentasanaccountingcost.AnexampleisgiveninthetextinwhichHelenrunsacookiebusiness,butshecouldinsteadworkasacomputerprogrammer.Becauseshe'sworkinginhercookiefactory,shegivesuptheopportunitytoearn$100perhourasacomputerprogrammer.Theaccountantignoresthisopportunitycostbecausenomoneyflowoccurs.ButthecostisrelevanttoHelen'sdecisiontorunthecookiefactory.Q3Whatismarginalproduct,andwhatdoesitmeansifitisdiminishing?Marginalproductistheincreaseinoutputthatarisesfromanadditionalunitofinput.Diminishingmarginalproductmeansthatthemarginalproductofaninputdeclinesasthequantityoftheinputincreases.Q8Defindeconomiesofscaleandexplainwhytheymightarise.Definediseconomiesofscaleandexplainwhythenmightarise.Economiesofscaleexistwhenlong-runaveragetotalcostfallsasthequantityofoutputincreases,whichoccursbecauseofspecializationamongworkers.Diseconomiesofscaleexistwhenlong-runaveragetotalcostrisesasthequantityofoutputincreases,whichoccursbecauseofcoordinationproblemsinherentinalargeorganization.14Q2Drawthecostcurvesforatypicalfirm.Foragivenprice,explainhowthefirmchoosesthelevelofoutputthatmaximizesprofit.Figure2showsthecostcurvesforatypicalfirm.Foragivenprice(suchasP*),thelevelofoutputthatmaximizesprofitistheoutputwheremarginalcostequalsprice(Q*),aslongaspriceisgreaterthanaveragevariablecostatthatpoint(intheshortrun),orgreaterthanaveragetotalcost(inthelongrun).Figure2Q6Doesafirm’spriceequalmarginalcostintheshortrun,inthelongrun,orboth?Explain.Thefirm'spriceequalstheminimumofaveragetotalcostonlyinthelongrun.Intheshortrun,pricemaybegreaterthanaveragetotalcost,inwhichcasethefirmismakingprofits,orpricemaybelessthanaveragetotalcost,inwhichcasethefirmismakinglosses.Butthesituationisdifferentinthelongrun.Iffirmsaremakingprofits,otherfirmswillentertheindustry,whichwilllowerthepriceofthegood.Iffirmsaremakinglosses,theywillexittheindustry,whichwillraisethepriceofthegood.Entryorexitcontinuesuntilfirmsaremakingneitherprofitsnorlosses.Atthatpoint,priceequalsaveragetotalcost.15Q3Whyismonopolist’smarginalrevenuelessthanthepriceofitsgoods?Canmarginalrevenuebenegative?Explain.Amonopolist'smarginalrevenueislessthanthepriceofitsproductbecause:(1)itsdemandcurveisthemarketdemandcurve,so(2)toincreasetheamountsold,themonopolistmustlowerthepriceofitsgoodforeveryunititsells.(3)Thiscutinpricesreducesrevenueontheunitsitwasalreadyselling.Amonopolist'smarginalrevenuecanbenegativebecausetogetpurchaserstobuyanadditionalunitofthegood,thefirmmustreduceitspriceonallunitsofthegood.Thefactthatitsellsagreaterquantityincreasesrevenue,butthedeclineinpricedecreasesrevenue.Theoveralleffectdependsontheelasticityofthedemandcurve.Ifthedemandcurveisinelastic,marginalrevenuewillbenegative.Q4Drawthedemand,marginal-revenue,andmarginal-costcurveforamonopolist.Showtheprofit-maximizinglevelofoutput.Showtheprofit-maximizingprice.Figure1showsthedemand,marginal-revenue,andmarginal-costcurvesforamonopolist.Theintersectionofthemarginal-revenueandmarginal-costcurvesdeterminestheprofit-maximizinglevelofoutput,Qm.Thedemandcurvethenshowstheprofit-maximizingprice,Pm.Figure116Q1Ifagroupofsellerscouldformacartel,whatquantityandpricewouldtheytrytoset?Ifagroupofsellerscouldformacartel,theywouldtrytosetquantityandpricelikeamonopolist.Theywouldsetquantityatthepointwheremarginalrevenueequalsmarginalcost,andsetpriceatthecorrespondingpointonthedemandcurve.Q5Whatistheprisoners’dilemmaandwhatdoesithavetodowitholigopoly?Theprisoners'dilemmaisagamebetweentwopeopleorfirmsthatillustrateswhyitisdifficultforopponentstocooperateevenwhencooperationwouldmakethemallbetteroff.Eachpersonorfirmhasagreatincentivetocheatonanycooperativeagreementtomakehimselforitselfbetteroff.17Q2Drawadiagramofthelong-runequilibriuminamonopolisticallycompetitivemarket.Howispricerelatedtoaveragetotalcost?Howispricerelatedtomarginalcost?InFigure2,afirmhasdemandcurveD1andmarginal-revenuecurveMR1.ThefirmismakingprofitsbecauseatquantityQ1,price(P1)isaboveaveragetotalcost(ATC).Thoseprofitsinduceotherfirmstoentertheindustry,causingthedemandcurvetoshifttoD2andthemarginal-revenuecurvetoshifttoMR2.TheresultisadeclineinquantitytoQ2,atwhichpointtheprice(P2)equalsaveragetotalcost(ATC),soprofitsarenowzero.Figure223Q1Explainwhyaneconomy’sincomemustequalitsexpenditure.Aneconomy'sincomemustequalitsexpenditure,sinceeverytransactionhasabuyerandaseller.Thus,expenditurebybuyersmustequalincomebysellers.24Q2Describethethreeproblemsthatmaketheconsumerpriceindexanimperfectmeasureofthecostofliving.Thethreeproblemsintheconsumerpriceindexasameasureofthecostoflivingare:(1)substitutionbias,whicharisesbecausepeoplesubstitutetowardgoodsthathavebecomerelativelylessexpensive;(2)theintroductionofnewgoods,whicharenotreflectedquicklyintheCPI;and(3)unmeasuredqualitychange.25Q2Listanddescribefourdeterminantsofproductivity.Thefourdeterminantsofproductivityare:(1)physicalcapital,whichisthestockofequipmentandstructuresthatareusedtoproducegoodsandservices;(2)humancapital,whichconsistsoftheknowledgeandskillsthatworkersacquirethrougheducation,training,andexperience;(3)naturalresources,whichareinputsintoproductionthatareprovidedbynature;and(4)technologicalknowledge,whichissociety’sunderstandingofthebestwaystoproducegoodsandservices.Questionsarechosenfromproblemsandapplications.Chapter1:Q9Byspecializingineachtask,youandyourroommatecanfinishthechoresmorequickly.Ifyoudividedeachtaskequally,itwouldtakeyoumoretimetocookthanitwouldtakeyourroommate,anditwouldtakehimmoretimetocleanthanitwouldtakeyou.Byspecializing,youreducethetotaltimespentonchores.Similarly,countriescanspecializeandtrade,makingbothbetteroff.Forexample,supposeittakesSpanishworkerslesstimetomakeclothesthanFrenchworkers,andFrenchworkerscanmakewinemoreefficientlythanSpanishworkers.ThenSpainandFrancecanbothbenefitifSpanishworkersproducealltheclothesandFrenchworkersproduceallthewine,andtheyexchangesomewineforsomeclothes.Chapter2:Q2a.Figure6showsaproductionpossibilitiesfrontierbetweengunsandbutter.Itisbowedoutbecausewhenmostoftheeconomy’sresourcesarebeingusedtoproducebutter,thefrontierissteepandwhenmostoftheeconomy’sresourcesarebeingusedtoproduceguns,thefrontierisveryflat.Whentheeconomyisproducingalotofguns,workersandmachinesbestsuitedtomakingbutterarebeingusedtomakeguns,soeachunitofgunsgivenupyieldsalargeincreaseintheproductionofbutter.Thus,theproductionpossibilitiesfrontierisflat.Whentheeconomyisproducingalotofbutter,workersandmachinesbestsuitedtomakinggunsarebeingusedtomakebutter,soeachunitofgunsgivenupyieldsasmallincreaseintheproductionofbutter.Thus,theproductionpossibilitiesfrontierissteep.b.PointAisimpossiblefortheeconomytoachieve;itisoutsidetheproductionpossibilitiesfrontier.PointBisfeasiblebutinefficientbecauseit’sinsidetheproductionpossibilitiesfrontier.Figure6c.TheHawksmightchooseapointlikeH,withmanygunsandnotmuchbutter.TheDovesmightchooseapointlikeD,withalotofbutterandfewguns.d.IfbothHawksandDovesreducedtheirdesiredquantityofgunsbythesameamount,theHawkswouldgetabiggerpeacedividendbecausetheproductionpossibilitiesfrontierismuchsteeperatpointHthanatpointD.Asaresult,thereductionofagivennumberofguns,startingatpointH,leadstoamuchlargerincreaseinthequantityofbutterproducedthanwhenstartingatpointD.Chapter3:Q4a.SinceaCanadianworkercanmakeeithertwocarsayearor30bushelsofwheat,theopportunitycostofacaris15bushelsofwheat.Similarly,theopportunitycostofabushelofwheatis1/15ofacar.Theopportunitycostsarethereciprocalsofeachother.b.SeeFigure4.Ifall10millionworkersproducetwocarseach,theyproduceatotalof20millioncars,whichistheverticalinterceptoftheproductionpossibilitiesfrontier.Ifall10millionworkersproduce30bushelsofwheateach,theyproduceatotalof300millionbushels,whichisthehorizontalinterceptoftheproductionpossibilitiesfrontier.Sincethetradeoffbetweencarsandwheatisalwaysthesame,theproductionpossibilitiesfrontierisastraightline.IfCanadachoosestoconsume10millioncars,itwillneed5millionworkersdevotedtocarproduction.Thatleaves5millionworkerstoproducewheat,whowillproduceatotalof150millionbushels(5millionworkerstimes30bushelsperworker).ThisisshownaspointAonFigure4.c.IftheUnitedStatesbuys10millioncarsfromCanadaandCanadacontinuestoconsume10millioncars,thenCanadawillneedtoproduceatotalof20millioncars.SoCanadawillbeproducingattheverticalinterceptoftheproductionpossibilitiesfrontier.ButifCanadagets20bushelsofwheatpercar,itwillbeabletoconsume200millionbushelsofwheat,alongwiththe10millioncars.ThisisshownaspointBinthefigure.Canadashouldacceptthedealbecauseitgetsthesamenumberofcarsand50millionmorebushesofwheat.Figure4Chapter4:Q1a.Coldweatherdamagestheorangecrop,reducingthesupplyoforanges.ThiscanbeseeninFigure6asashifttotheleftinthesupplycurvefororanges.Thenewequilibriumpriceishigherthantheoldequilibriumprice.b.PeopleoftentraveltotheCaribbeanfromNewEnglandtoescapecoldweather,sodemandforCaribbeanhotelroomsishighinthewinter.Inthesummer,fewerpeopletraveltotheCaribbean,sincenorthernclimesaremorepleasant.Theresult,asshowninFigure7,isashifttotheleftinthedemandcurve.TheequilibriumpriceofCaribbeanhotelroomsisthuslowerinthesummerthaninthewinter,asthefigureshows.Figure6aFigure7bc.WhenawarbreaksoutintheMiddleEast,manymarketsareaffected.Sincemuchoilproductiontakesplacethere,thewardisruptsoilsupplies,shiftingthesupplycurveforgasolinetotheleft,asshowninFigure8.Theresultisariseintheequilibriumpriceofgasoline.Withahigherpriceforgasoline,thecostofoperatingagas-guzzlingautomobile,likeaCadillac,willincrease.Asaresult,thedemandforusedCadillacswilldecline,aspeopleinthemarketforcarswillnotfindCadillacsasattractive.Inaddition,somepeoplewhoalreadyownCadillacswilltrytosellthem.TheresultisthatthedemandcurveforusedCadillacsshiftstotheleft,whilethesupplycurveshiftstotheright,asshowninFigure9.TheresultisadeclineintheequilibriumpriceofusedCadillacs.Figure8cFigure9cChapter5:Q2a.Forbusinesstravelers,thepriceelasticityofdemandwhenthepriceofticketsrisesfrom$200to$250is[(2,000-1,900)/1,950]/[(250-200)/225]=0.05/0.22=0.23.Forvacationers,thepriceelasticityofdemandwhenthepriceofticketsrisesfrom$200to$250is[(800-600)/700]/[(250-200)/225]=0.29/0.22=1.32.b.Thepriceelasticityofdemandforvacationersishigherthantheelasticityforbusinesstravelersbecausevacationerscanchoosemoreeasilyadifferentmodeoftransportation(likedrivingortakingthetrain).Businesstravelersarelesslikelytodososincetimeismoreimportanttothemandtheirschedulesarelessadaptable.Chapter6:Q2a.TheimpositionofabindingpricefloorinthecheesemarketisshowninFigure3.Intheabsenceofthepricefloor,thepricewouldbeP1andthequantitywouldbeQ1.WiththefloorsetatPf,whichisgreaterthanP1,thequantitydemandedisQ2,whilequantitysuppliedisQ3,sothereisasurplusofcheeseintheamountQ3–Q2.b.Thefarmers’complaintthattheirtotalrevenuehasdeclinediscorrectifdemandiselastic.Withelasticdemand,thepercentagedeclineinquantitywouldexceedthepercentageriseinprice,sototalrevenuewoulddecline.c.Ifthegovernmentpurchasesallthesurpluscheeseatthepricefloor,producersbenefitandtaxpayerslose.ProducerswouldproducequantityQ3ofcheese,andtheirtotalrevenuewouldincreasesubstantially.ButconsumerswouldbuyonlyquantityQ2ofcheese,sotheyareinthesamepositionasbefore.Taxpayerslosebecausetheywouldbefinancingthepurchaseofthesurpluscheesethroughhighertaxes.Figure3aChapter7:Q8a.Theeffectoffallingproductioncostsinthemarketforcomputersresultsinashifttotherightinthesupplycurve,asshowninFigure14.Asaresult,theequilibriumpriceofcomputersdeclinesandtheequilibriumquantityincreases.ThedeclineinthepriceofcomputersincreasesconsumersurplusfromareaAtoA+B+C+D,anincreaseintheamountB+C+D.Priortotheshiftinsupply,producersurpluswasareasB+E(theareaabovethesupplycurveandbelowtheprice).Aftertheshiftinsupply,producersurplusisareasE+F+G.SoproducersurpluschangesbytheamountF+G–B,whichmaybepositiveornegative.Theincreaseinquantityincreasesproducersurplus,whilethedeclineinthepricereducesproducersurplus.SinceconsumersurplusrisesbyB+C+DandproducersurplusrisesbyF+G–B,totalsurplusrisesbyC+D+F+G.Figure14AFigure15bb.Sinceaddingmachinesaresubstitutesforcomputers,thedeclineinthepriceofcomputersmeansthatpeoplesubstitutecomputersforaddingmachines,shiftingthedemandforaddingmachinestotheleft,asshowninFigure15.Theresultisadeclineinboththeequilibriumpriceandequilibriumquantityofaddingmachines.Consumersurplusintheadding-machinemarketchangesfromareaA+BtoA+C,anetchangeofC–B.ProducersurpluschangesfromareaC+D+EtoareaE,anetlossofC+D.Addingmachineproducersaresadabouttechnologicaladvanceincomputersbecausetheirproducersurplusdeclines.c.Sincesoftwareandcomputersarecomplements,thedeclineinthepriceandincreaseinthequantityofcomputersmeansthatthedemandforsoftwareincreases,shiftingthedemandforsoftwaretotheright,asshowninFigure16.Theresultisanincreaseinboththepriceandquantityofsoftware.ConsumersurplusinthesoftwaremarketchangesfromB+CtoA+B,anetchangeofA–C.ProducersurpluschangesfromEtoC+D+E,anincreaseofC+D,sosoftwareproducersshouldbehappyaboutthetechnologicalprogressincomputers.d.Yes,thisanalysishelpsexplainwhyBillGatesisonetheworld’srichestmen,sincehiscompanyproducesalotofsoftwarethatisacomplementwithcomputersandtherehasbeentremendoustechnologicaladvanceincomputers.Figure16Chapter13:Q4a.Thefollowingtableshowsthemarginalproductofeachhourspentfishing: Hours Fish FixedCost VariableCost TotalCost MarginalProduct 0 0 $10 $0 $10 --- 1 10 10 5 15 10 2 18 10 10 20 8 3 24 10 15 25 6 4 28 10 20 30 4 5 30 10 25 25 2b.Figure7graphsthefisherman'sproductionfunction.Theproductionfunctionbecomesflatterasthenumberofhoursspentfishingincreases,illustratingdiminishingmarginalproduct.Figure7bFigure8cc.Thetableshowsthefixedcost,variablecost,andtotalcostoffishing.Fi