曼昆经济学原理第二章.ppt

2,ThinkingLikeanEconomist,ThinkingLikeanEconomist,EveryfieldofstudyhasitsownterminologyMathematicsintegralsaxiomsvectorspacesPsychologyegoidcognitivedissonanceLawpromissoryestoppeltortsvenuesEconomicssupplyopportunitycostelasticityconsumersurplusdemandcomparativeadvantagedeadweightloss,ThinkingLikeanEconomist,Economicstrainsyouto.Thinkintermsofalternatives.Evaluatethecostofindividualandsocialchoices.Examineandunderstandhowcertaineventsandissuesarerelated.,THEECONOMISTASASCIENTIST,Theeconomicwayofthinking.Involvesthinkinganalyticallyandobjectively.Makesuseofthescientificmethod.,TheScientificMethod:Observation,Theory,andMoreObservation,Usesabstractmodelstohelpexplainhowacomplex,realworldoperates.Developstheories,collects,andanalyzesdatatoevaluatethetheories.,TheRoleofAssumptions,Economistsmakeassumptionsinordertomaketheworldeasiertounderstand.Theartinscientificthinkingisdecidingwhichassumptionstomake.Economistsusedifferentassumptionstoanswerdifferentquestions.,EconomicModels,EconomistsusemodelstosimplifyrealityinordertoimproveourunderstandingoftheworldTwoofthemostbasiceconomicmodelsinclude:TheCircularFlowDiagramTheProductionPossibilitiesFrontier,OurFirstModel:TheCircular-FlowDiagram,Thecircular-flowdiagramisavisualmodeloftheeconomythatshowshowdollarsflowthroughmarketsamonghouseholdsandfirms.,Figure1TheCircularFlow,Copyright2004South-Western,Spending,Revenue,Income,=Flowofinputs,andoutputs,=Flowofdollars,OurFirstModel:TheCircular-FlowDiagram,FirmsProduceandsellgoodsandservicesHireandusefactorsofproductionHouseholdsBuyandconsumegoodsandservicesOwnandsellfactorsofproduction,OurFirstModel:TheCircular-FlowDiagram,MarketsforGoodsandServicesFirmssellHouseholdsbuyMarketsforFactorsofProductionHouseholdssellFirmsbuy,OurFirstModel:TheCircular-FlowDiagram,FactorsofProductionInputsusedtoproducegoodsandservicesLand,labor,andcapital,OurSecondModel:TheProductionPossibilitiesFrontier,Theproductionpossibilitiesfrontierisagraphthatshowsthecombinationsofoutputthattheeconomycanpossiblyproducegiventheavailablefactorsofproductionandtheavailableproductiontechnology.,Figure2TheProductionPossibilitiesFrontier,Copyright2003Southwestern/ThomsonLearning,Quantityof,CarsProduced,0,3,000,1,000,Quantityof,Computers,Produced,OurSecondModel:TheProductionPossibilitiesFrontier,ConceptsIllustratedbytheProductionPossibilitiesFrontierEfficiencyTradeoffsOpportunityCostEconomicGrowth,Figure3AShiftintheProductionPossibilitiesFrontier,Copyright2004South-Western,Quantityof,CarsProduced,0,Quantityof,Computers,Produced,MicroeconomicsandMacroeconomics,Microeconomicsfocusesontheindividualpartsoftheeconomy.HowhouseholdsandfirmsmakedecisionsandhowtheyinteractinspecificmarketsMacroeconomicslooksattheeconomyasawhole.Economy-widephenomena,includinginflation,unemployment,andeconomicgrowth,THEECONOMISTASPOLICYADVISOR,Wheneconomistsaretryingtoexplaintheworld,theyarescientists.Wheneconomistsaretryingtochangetheworld,theyarepolicyadvisor.,POSITIVEVERSUSNORMATIVEANALYSIS,Positivestatementsarestatementsthatattempttodescribetheworldasitis.CalleddescriptiveanalysisNormativestatementsarestatementsabouthowtheworldshouldbe.Calledprescriptiveanalysis,PositiveorNormativeStatements?Anincreaseintheminimumwagewillcauseadecreaseinemploymentamongtheleast-skilled.POSITIVEHigherfederalbudgetdeficitswillcauseinterestratestoincrease.POSITIVE,?,?,POSITIVEVERSUSNORMATIVEANALYSIS,?,PositiveorNormativeStatements?Theincomegainsfromahigherminimumwageareworthmorethananyslightreductionsinemployment.NORMATIVEStategovernmentsshouldbeallowedtocollectfromtobaccocompaniesthecostsoftreatingsmoking-relatedillnessesamongthepoor.NORMATIVE,?,?,POSITIVEVERSUSNORMATIVEANALYSIS,?,EconomistsinWashington,.serveasadvisersinthepolicymakingprocessofthethreebranchesofgovernment:LegislativeExecutiveJudicial,EconomistsinWashington,Somegovernmentagenciesthatcollecteconomicdataandmakeeconomicpolicy:DepartmentofCBureauofLaborStatisticsCongressionalBudgetOfficeFederalReserveBoard,WHYECONOMISTSDISAGREE,Theymaydisagreeaboutthevalidityofalternativepositivetheoriesabouthowtheworldworks.Theymayhavedifferentvaluesand,therefore,differentnormativeviewsaboutwhatpolicyshouldtrytoaccomplish.,Table2TenPropositionsaboutWhichMostEconomistsAgree,Copyright2004South-Western,Summary,Economiststrytoaddresstheirsubjectswithascientistsobjectivity.Theymakeappropriateassumptionsandbuildsimplifiedmodelsinordertounderstandtheworldaroundthem.Twosimpleeconomicmodelsarethecircular-flowdiagramandtheproductionpossibilitiesfrontier.,Summary,Economicsisdividedintotwosubfields:Microeconomistsstudydecisionmakingbyhouseholdsandfirmsinthemarketplace.Macroeconomistsstudytheforcesandtrendsthataffecttheeconomyasawhole,Summary,Apositivestatementisanassertionabouthowtheworldis.Anormativestatementisanassertionabouthowtheworldoughttobe.Wheneconomistsmakenormativestatements,theyareactingmoreas