曼昆版微观经济学西方经济学 35页

1PRINCIPLESOFFOURTHEDITIONTenPrinciplesofEconomics\nInthischapter,lookfortheanswerstothesequestions:Whatkindsofquestionsdoeseconomicsaddress?Whataretheprinciplesofhowpeoplemakedecisions?Whataretheprinciplesofhowpeopleinteract?Whataretheprinciplesofhowtheeconomyasawholeworks?CHAPTER1TENPRINCIPLESOFECONOMICS\nWhatEconomicsIsAllAboutScarcityreferstothelimitednatureofsociety’sresources.Economicsisthestudyofhowsocietymanagesitsscarceresources,includinghowpeopledecidehowmuchtowork,save,andspend,andwhattobuyhowfirmsdecidehowmuchtoproduce,howmanyworkerstohirehowsocietydecideshowtodivideitsresourcesbetweennationaldefense,consumergoods,protectingtheenvironment,andotherneeds0CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEMAKEDECISIONSDecisionmakingisattheheartofeconomics.Thefirstfourprinciplesdealwithhowpeoplemakedecisions.0CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEMAKEDECISIONSAlldecisionsinvolvetradeoffs.Examples:Goingtoapartythenightbeforeyourmidtermleaveslesstimeforstudying.Havingmoremoneytobuystuffrequiresworkinglongerhours,whichleaveslesstimeforleisure.Protectingtheenvironmentrequiresresourcesthatmightotherwisebeusedtoproduceconsumergoods.Principle#1:PeopleFaceTradeoffs0CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEMAKEDECISIONSSocietyfacesanimportanttradeoff:efficiencyvs.equityefficiency:gettingthemostoutofscarceresourcesequity:distributingprosperityfairlyamongsociety’smembersTradeoff:Toincreaseequity,canredistributeincomefromthewell-offtothepoor.Butthisreducestheincentivetoworkandproduce,andshrinksthesizeoftheeconomic“pie.”Principle#1:PeopleFaceTradeoffs0CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEMAKEDECISIONSMakingdecisionsrequirescomparingthecostsandbenefitsofalternativechoices.Theopportunitycostofanyitemiswhatevermustbegivenuptoobtainit.Itistherelevantcostfordecisionmaking.Principle#2:TheCostofSomethingIsWhatYouGiveUptoGetItCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEMAKEDECISIONSExamples:Theopportunitycostof……goingtocollegeforayearisnotjustthetuition,books,andfees,butalsotheforegonewages.…seeingamovieisnotjustthepriceoftheticket,butthevalueofthetimeyouspendinthetheater.Principle#2:TheCostofSomethingIsWhatYouGiveUptoGetItCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEMAKEDECISIONSApersonisrationalifshesystematicallyandpurposefullydoesthebestshecantoachieveherobjectives.Manydecisionsarenot“allornothing,”butinvolvemarginalchanges–incrementaladjustmentstoanexistingplan.Evaluatingthecostsandbenefitsofmarginalchangesisanimportantpartofdecisionmaking.Principle#3:RationalPeopleThinkattheMarginCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEMAKEDECISIONSExamples:Astudentconsiderswhethertogotocollegeforanadditionalyear,comparingthefees&foregonewagestotheextraincomehecouldearnwithanextrayearofeducation.Afirmconsiderswhethertoincreaseoutput,comparingthecostoftheneededlaborandmaterialstotheextrarevenue.Principle#3:RationalPeopleThinkattheMarginCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEMAKEDECISIONSincentive:somethingthatinducesapersontoact,i.e.theprospectofarewardorpunishment.Rationalpeoplerespondtoincentivesbecausetheymakedecisionsbycomparingcostsandbenefits.Examples:Inresponsetohighergasprices,salesof“hybrid”cars(e.g.,ToyotaPrius)rise.Inresponsetohighercigarettetaxes,teensmokingfalls.Principle#4:PeopleRespondtoIncentivesCHAPTER1TENPRINCIPLESOFECONOMICS\nACTIVELEARNING1:ExerciseYouaresellingyour1996Mustang.Youhavealreadyspent$1000onrepairs.Atthelastminute,thetransmissiondies.Youcanpay$600tohaveitrepaired,orsellthecar“asis.”Ineachofthefollowingscenarios,shouldyouhavethetransmissionrepaired?A.Bluebookvalueis$6500iftransmissionworks,$5700ifitdoesn’tB.Bluebookvalueis$6000iftransmissionworks,$5500ifitdoesn’t11CHAPTER1TENPRINCIPLESOFECONOMICS\nACTIVELEARNING1:AnswersCostoffixingtransmission=$600A.Bluebookvalueis$6500iftransmissionworks,$5700ifitdoesn’tBenefitoffixingthetransmission=$800($6500–5700).It’sworthwhiletohavethetransmissionfixed.B.Bluebookvalueis$6000iftransmissionworks,$5500ifitdoesn’tBenefitoffixingthetransmissionisonly$500.Paying$600tofixtransmissionisnotworthwhile.12CHAPTER1TENPRINCIPLESOFECONOMICS\nACTIVELEARNING1:AnswersObservations:The$1000youpreviouslyspentonrepairsisirrelevant.Whatmattersisthecostandbenefitofthemarginalrepair(thetransmission).ThechangeinincentivesfromscenarioAtoscenarioBcausedyourdecisiontochange.13CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEINTERACTAn“economy”isjustagroupofpeopleinteractingwitheachother.Thenextthreeprinciplesdealwithhowpeopleinteract.0CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEINTERACTRatherthanbeingself-sufficient,peoplecanspecializeinproducingonegoodorserviceandexchangeitforothergoods.Countriesalsobenefitfromtrade&specialization:getabetterpriceabroadforgoodstheyproducebuyothergoodsmorecheaplyfromabroadthancouldbeproducedathomePrinciple#5:TradeCanMakeEveryoneBetterOffCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEINTERACTAmarketisagroupofbuyersandsellers.(Theyneednotbeinasinglelocation.)“Organizeeconomicactivity”meansdeterminingwhatgoodstoproducehowtoproducethemhowmuchofeachtoproducewhogetsthemPrinciple#6:MarketsAreUsuallyAGoodWaytoOrganizeEconomicActivityCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEINTERACTInamarketeconomy,thesedecisionsresultfromtheinteractionsofmanyhouseholdsandfirms.FamousinsightbyAdamSmithinTheWealthofNations(1776):Eachofthesehouseholdsandfirmsactsasif“ledbyaninvisiblehand”topromotegeneraleconomicwell-being.Principle#6:MarketsAreUsuallyAGoodWaytoOrganizeEconomicActivityCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEINTERACTTheinvisiblehandworksthroughthepricesystem:Theinteractionofbuyersandsellersdeterminespricesofgoodsandservices.Eachpricereflectsthegood’svaluetobuyersandthecostofproducingthegood.Pricesguideself-interestedhouseholdsandfirmstomakedecisionsthat,inmanycases,maximizesociety’seconomicwell-being.Principle#6:MarketsAreUsuallyAGoodWaytoOrganizeEconomicActivityCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEINTERACTImportantroleforgovt:enforcepropertyrights(withpolice,courts)Peoplearelessinclinedtowork,produce,invest,orpurchaseiflargeriskoftheirpropertybeingstolen.Arestaurantwon’tservemealsifcustomersdonotpaybeforetheyleave.Amusiccompanywon’tproduceCDsiftoomanypeopleavoidpayingbymakingillegalcopies.Principle#7:GovernmentsCanSometimesImproveMarketOutcomesCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEINTERACTGovtmayaltermarketoutcometopromoteefficiencymarketfailure,whenthemarketfailstoallocatesociety’sresourcesefficiently.Causes:externalities,whentheproductionorconsumptionofagoodaffectsbystanders(e.g.pollution)marketpower,asinglebuyerorsellerhassubstantialinfluenceonmarketprice(e.g.monopoly)Insuchcases,publicpolicymayincreaseefficiency.Principle#7:GovernmentsCanSometimesImproveMarketOutcomesCHAPTER1TENPRINCIPLESOFECONOMICS\nHOWPEOPLEINTERACTGovtmayaltermarketoutcometopromoteequityIfthemarket’sdistributionofeconomicwell-beingisnotdesirable,taxorwelfarepoliciescanchangehowtheeconomic“pie”isdivided.Principle#7:GovernmentsCanSometimesImproveMarketOutcomesCHAPTER1TENPRINCIPLESOFECONOMICS\nACTIVELEARNING2:DiscussionQuestionsIneachofthefollowingsituations,whatisthegovernment’srole?Doesthegovernment’sinterventionimprovetheoutcome?a.PublicschoolsforK-12b.Workplacesafetyregulationsc.Publichighwaysd.Patentlaws,whichallowdrugcompaniestochargehighpricesforlife-savingdrugs22CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWTHEECONOMYASAWHOLEWORKSThelastthreeprinciplesdealwiththeeconomyasawhole.0CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWTHEECONOMYASAWHOLEWORKSHugevariationinlivingstandardsacrosscountriesandovertime:Averageincomeinrichcountriesismorethantentimesaverageincomeinpoorcountries.TheU.S.standardoflivingtodayisabouteighttimeslargerthan100yearsago.Principle#8:Acountry’sstandardoflivingdependsonitsabilitytoproducegoods&services.CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWTHEECONOMYASAWHOLEWORKSThemostimportantdeterminantoflivingstandards:productivity,theamountofgoodsandservicesproducedperunitoflabor.Productivitydependsontheequipment,skills,andtechnologyavailabletoworkers.Otherfactors(e.g.,laborunions,competitionfromabroad)havefarlessimpactonlivingstandards.Principle#8:Acountry’sstandardoflivingdependsonitsabilitytoproducegoods&services.CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWTHEECONOMYASAWHOLEWORKSInflation:increasesinthegenerallevelofprices.Inthelongrun,inflationisalmostalwayscausedbyexcessivegrowthinthequantityofmoney,whichcausesthevalueofmoneytofall.Thefasterthegovtcreatesmoney,thegreatertheinflationrate.Principle#9:Pricesrisewhenthegovernmentprintstoomuchmoney.CHAPTER1TENPRINCIPLESOFECONOMICS\nHOWTHEECONOMYASAWHOLEWORKSIntheshort-run(1–2years),manyeconomicpoliciespushinflationandunemploymentinoppositedirections.Otherfactorscanmakethistradeoffmoreorlessfavorable,butthetradeoffisalwayspresent.Principle#10:Societyfacesashort-runtradeoffbetweeninflationandunemploymentCHAPTER1TENPRINCIPLESOFECONOMICS\nFYI:HowtoReadYourTextbook1.Summarize,don’thighlight.Highlightingisapassiveactivitythatwon’timproveyourcomprehensionorretention.Instead,summarizeeachsectioninafewsentencesofyourownwords.Whenyoufinish,compareyoursummarytotheoneattheendofthechapter.2.Testyourself.Trythe“QuickQuiz”thatfollowseachsectionbeforemovingontothenextsection.Writeyouranswersdown,andcomparethemtotheanswersinthebackofthebook.Ifyouranswersareincorrect,reviewthesectionbeforemovingon.CHAPTER1TENPRINCIPLESOFECONOMICS\nFYI:HowtoReadYourTextbook3.Practice,practice,practice.Workthroughtheend-of-chapterreviewquestionsandproblems.Theyareoftengoodpracticefortheexams.Andthemoreyouuseyournewknowledge,themoresoliditwillbecome.4.Goonline.Thebookcomeswithexcellentwebresources,includingpracticequizzes,toolstostrengthenyourgraphingskills,helpfulvideoclips,andotherresourcestohelpyoulearnthetextbookmaterialmoreeasilyandeffectively.CHAPTER1TENPRINCIPLESOFECONOMICS\nFYI:HowtoReadYourTextbook5.Studyingroups.Gettogetherwithafewofyourclassmatestorevieweachchapter,quizeachother,andhelpeachotherunderstandthematerialinthechapter.6.Don’tforgettherealworld.ReadtheCaseStudiesandInTheNewsboxesineachchapter.Theywillhelpyouseehowthenewterms,concepts,models,andgraphsapplytotherealworld.Asyoureadthenewspaperorwatchtheeveningnews,seeifyoucanfindtheconnectionswithwhatyou’relearninginthetextbook.CHAPTER1TENPRINCIPLESOFECONOMICS\nCONCLUSIONEconomicsoffersmanyinsightsaboutthebehaviorofpeople,markets,andeconomies.Itisbasedonafewideasthatcanbeappliedinmanysituations.WheneverwereferbacktooneoftheTenPrinciplesfromthischapter,youwillseeaniconlikethisone:CHAPTER1TENPRINCIPLESOFECONOMICS\nCHAPTERSUMMARYTheprinciplesofdecisionmakingare:Peoplefacetradeoffs.Thecostofanyactionismeasuredintermsofforegoneopportunities.Rationalpeoplemakedecisionsbycomparingmarginalcostsandmarginalbenefits.Peoplerespondtoincentives.CHAPTER1TENPRINCIPLESOFECONOMICS\nCHAPTERSUMMARYTheprinciplesofinteractionsamongpeopleare:Tradecanbemutuallybeneficial.Marketsareusuallyagoodwayofcoordinatingtrade.Govtcanpotentiallyimprovemarketoutcomesifthereisamarketfailureorifthemarketoutcomeisinequitable.CHAPTER1TENPRINCIPLESOFECONOMICS\nCHAPTERSUMMARYTheprinciplesoftheeconomyasawholeare:Productivityistheultimatesourceoflivingstandards.Moneygrowthistheultimatesourceofinflation.Societyfacesashort-runtradeoffbetweeninflationandunemployment.CHAPTER1TENPRINCIPLESOFECONOMICS