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1、CHAPTER20ADVANCEDTOPICSSolutionstotheProblemsintheTextbook:ConceptualProblems:1.Someoftheaspectsofthetheoriesdiscussedinthischaptercomplementeachother,buttherearealsomajordisagreements.Therealbusinesscycletheoryisanoutgrowthoftherationalexpectationstheoryandtherandomwalkof
2、GDPtheory,whilethenewKeynesianmodelsrespondtotherationalexpectationstheorybyshowingwhypricesmaystillbestickyevenundertheassumptionofrationalexpectations.InboththerealbusinesscycletheoryandthenewKeynesianmodels,expectationsareformedrationally,butonlytherealbusinesscycletheo
3、ryassumesthatmarketsclearveryrapidly.Thesetheoriesthereforedisagreeonthespeedofthepriceadjustment.Theyalsodisagreeonthesourcesofshockstotheeconomy.Thequestionofwhetheroutputfollowsarandomwalkhasalsobeenanimportantpointofdisagreement.Ifoutputshocksareimportanttheymustcomefr
4、omthesupplysideandtheymusthavepermanenteffects.2.Rationalexpectationsdifferfromperfectforesightinthatexpectationsareimperfect.Whilerationalpeoplewillmakeefficientuseofallinformationavailable,theymaystillmakeincorrectforecasts.However,whenexpectationsarerational,nosystemati
5、cerrorsaremade.Thebestguessfortheforecasterrortermiszero.Underperfectforesight,monetarypolicyisalwaysneutral,thatis,theeffectofmonetarypolicyonrealoutputiszeroevenintheshortrun.Underrationalexpectations,monetarypolicyhasashort-runeffectonoutputifthepolicychangeisunanticipa
6、ted,butitisneutralinthelongrun.3.Thepropagationmechanismistheprocessbywhichadisturbancespreadsthroughtheeconomy.Theconceptofintertemporalsubstitutionofleisureismostoftenusedtodescribewhypeopleworkmoreinsomeperiodsthaninothers.Assume,forexample,thatthereisanegativeshocktote
7、chnologysuchthatthemarginalproductoflabor(andthereforetherealwagerate)dropstemporarilyuntilthemarketclears.Workersrealizethat,forthenearfuturetherealwagerateislowerthanusual.Thereforetheymaychoosetotakesometimeofforworkfewerhoursthanusual,intendingtomakeupforitlaterwhenthe
8、wageratehasincreasedagain.Inthisway,asmallchangeinwages(resultingfromashockintechnology)c
