曼昆經(jīng)濟學原理英文版文案加習題答案30章

1、曼昆經(jīng)濟學原理英文版文案加習題答案3章28130WHDSSDDDDHDDDDDDDDHDDDDDDDD：Thereuareunoumajoruchangesutouthisiichapter.LEARNINGOBJECTIVESByutheuenduofuthisuchapteruustudentsushouidiiunderstand：whyuinfiationuresuitsufromurapidugrowthuinutheumoneyusuppiy.theumeaninguofutheuciassicaiudichotomyuandumonetaryuneutraiity.whyusom

2、eucountriesuprintusoumuchumoneyuthatutheyuexperienceuhyperinfiation.howutheunominaiuinteresturateurespondsutoutheuinfiationurate.theuvariousucostsuthatuinfiationuimposesuonusociety.xduoddupudpd:ohapterui7uisutheuseconduchapteruinuautwo-chapterusequenceudeaiinguwithumoneyuandupricesuinutheuiongurunou

3、ohapterui6uexpiaineduwhatumoneyuisuanduhowutheuFederaiuoeserveumoneyouohapterui7uestabiishesutheureiationshipubetweenutheurateuofugrowthuofumoneyuandutheuinfiationurateouDheupurposeuofuthisuchapteruisutouacquaintustudentsuwithutheuc(studentsuwiiiufinduthatuuinutheuiongurunuuthereuisuaustrongureiatio

4、nshipubetweenutheugrowthurateuofumoneyuanduinfiationuustudentsuwiiiuaisoufinduthatuthereuareunumerousucinfiation,ubututhatuthereuisunotuauconsensusuonutheuimportanceuofutheseucostsuwhenuinfiationuisumoderate.keyupointsuheuoveraiiuieveiuofupricesuinuanueconomyuadjustsutoubringumoneyusuppiyuandumoneyu

5、demanduintoubaiance.uwhenutheucentraiubankuincreasesutheusuppiyuofumoneyuuitucausesutheupersistentugrowthuinutheuquantityuofumoneyusuppiieduieadsutoucontinuinguinfiation.mdddyudddddhuoddINFLATION282?Chapterui7/Moneyuurowthuanduinfiationuoheuprincipieuofumonetaryuneutraiityuassertsuthatuchangesuinuth

6、euquantityuofumoneyuinfiuenceunominaiuvariabiesubutunotureaiuvariabiesouMostueconomistsubeiieveuthatumoneidescribesutheubehavioruofutheueconomyuinutheuiongurun.uAugovernmentucanupayuforusomeuofuitsuspendingusimpiyubyuprintingumoney.uwhenucountriesureiyuheaviiyuonuthisu“infiationutax,”utheuresuituisu

7、hyperinfiation.uDneuappiicationuofutheuprincipieuofumonetaryuneutraiityuisutheuFisherueffectouoccordingutoutheuFisherueffectDuwhenutheuinfiationurateurisesoutheunominaiuinteresturateurireaiuinteresturateuremainsutheusame.uManyupeopieuthinkuthatuinfiationumakesuthemupoorerubecauseuituraisesutheucostu

8、ofuwhatutheyubuy.uuhisuviewuisuaufaiiacy,uhowever,ubecauseuinfiationuaisouraisesunominaiuiuiiconomistsuhaveuidentifiedusixucostsuofuinfiation:ushoeieatherucostsuassociateduwithureducedumoneyuhoidings,umenuucostsuassociateduwithumoreufrequentuadjustmentuofupricreiativeuprices,uunintendeduchangesuinut

9、axuiiabiiitiesudueutounonindexationuofutheutaxucode,uconfusionuanduinconvenienceuresuitingufromuauchanginguunituofuaccount,uanduabetweenudebtorsuanducreditors.uManyuofutheseucostsuareuiargeuduringuhyperinfiation,ubututheusizeuoftheseucostsuforumoderateuinfiationuisuiessuciear.ohopdddududdddd:uuheuin

10、fiationurateuisumeasureduasutheupercentageuchangeuinutheuConsumerupriceuindexuutheuuDPdefiator,uorusomeuotheruindexuofutheuoveraiiupriceuievei.uOverutheupastu80uyears,upricesuhaveurisenuonuaverageu3.6%uperuyearuinutheuunitedustates.uuhereuhasubeenusubstantiaiuvariationuinutheurateuofupriceuchangesuo

11、verutime.uFromu2OO2utou2Oi2,upricesuroseuatuanuaverageurateuofu2.5%uperuyear,uwhiieupricesuroseuby7.8%uperuyearuduringutheui970s.uinternationaiudataushowsuanuevenubroaderurangeuofuinfiationuexperiences.uinu20i2,uinfiationuwasO.i%uinuuapan,u5.i%uinuiiussia,u9.3%uinuindia,uandu2i.i%uinuienezueia.ii.uu

12、heuciassicaiuuheoryuofuinfiationStaWoffthechaptertydiTereniiatirgoetweeuc勺吃肝d-fv-MI時別烹in皿a：ageI嗣濟pricesan:a血“咂incr眾如1:旭pricehie.A無no加sjibihotstideiterdi韭t”atinfkbri低邪dirttheaveragehrelofprirajintheuwhenutheupriceuieveiurises,upeopieuhaveutoupayumoreuforutheugoodsuanduservicesutheyubuy.uAuriseuinuthe

13、upriceuieveiuaisoumeansuthatutheuvaiueuofumoneyuisunowuiowerubecauseueachudoiiarnowubuysuausmaiieruquantityuofugoodsuanduservices.IfPisthepricelevel,thenthequantityofgoodsandservicesthatcanbepurchasedwith$1isequalto1/P.Supposeyouliveinacountrywithonegood(icecreamcones).Whenthepriceofanicecreamconeis

14、$2,thevalueofadollaris1/2cone.Whenthepriceofanicecreamconerisesto$3,thevalueofadollaris1/3cone.MoneySupply,MoneyDemand,andMonetaryEquilibriumThevalueofmoneyisdeterminedbythesupplyanddemandformoney.Forthemostpart,thesupplyofmoneyisdeterminedbytheFed.Thedemandformoneyreflectshowmuchwealthpeoplewanttoh

15、oldinliquidform.Onevariablethatisveryimportantindeterminingthedemandformoneyisthepricelevel.Thehigherpricesare,themoremoneythatisneededtoperformtransactions.Thus,ahigherpricelevel(andalowervalueofmoney)leadstoahigherquantityofmoneydemanded.Inthelongrun,moneysupplyandmoneydemandarebroughtintoequilibr

16、iumbytheoveralllevelofprices.Ifthepricelevelisabovetheequilibriumlevel,peoplewillwanttoholdmoremoneythanisavailableandpriceswillhavetodecline.Ifthepricelevelisbelowequilibrium,peoplewillwanttoholdlessmoneythanthatavailableandthepricelevelwillrise.Wecanshowthesupplyanddemandformoneyusingagraph.Thehor

17、izontalaxisshowsthequantityofmoney.Theleft-handverticalaxisisthevalueofmoney,measuredby1/P.Theright-handverticalaxisisthepricelevel(P).Notethatitisinvertedahighvalueofmoneymeansalowpricelevelandviceversa.284?Chapter17/MoneyGrowthandInflationThesupplycurveisverticalbecausetheFedhasfixedthequantityofm

18、oneyavailable.Thedemandcurveformoneyisdownwardsloping.Whenthevalueofmoneyislow,peopledemandalargerquantityofittobuygoodsandservices.Attheequilibrium,thequantityofmoneydemandedisequaltothequantityofmoneysupplied.TheEffectsofaMonetaryInjectionAssumethattheeconomyiscurrentlyinequilibriumandtheFedsudden

19、lyincreasesthesupplyofmoney.Thesupplyofmoneyshiftstotheright.ValueofMoney1/P(high)EquilibriumValueofMoney(low)Pricelevel(i(low)EquilibPriceL(high)QuantityofMoneyTheequilibriumvalueofmoneyfallsandthepricelevelrises.Whenanincreaseinthemoneysupplymakesdollarsmoreplentiful,theresultisanincreaseinthepric

20、elevelthatmakeseachdollarlessvaluable.Definitionofquantitytheoryofmoney:atheoryassertingthatthequantityofmoneyavailabledeterminesthepricelevelandthatthegrowthrateinthequantityofmoneyavailabledeterminestheinflationrate.ABriefLookattheAdjustmentProcessTheimmediateeffectofanincreaseinthemoneysupplyisto

21、createanexcesssupplyofmoney.Peopletrytogetridofthisexcesssupplyinavarietyofways.Theymaybuygoodsandserviceswiththeexcessfunds.Theymayusetheseexcessfundstomakeloanstoothersbybuyingbondsordepositingthemoneyinabankaccount.Theseloanswillthenbeusedbyotherstobuygoodsandservices.Chapter17/MoneyGrowthandInfl

22、ation?285Ineithercase,theincreaseinthemoneysupplyleadstoanincreaseinthedemandforgoodsandservices.Becausethesupplyofgoodsandserviceshasnotchanged,theresultofanincreaseinthedemandforgoodsandserviceswillbehigherprices.TheClassicalDichotomyandMonetaryNeutralityInthe18thcentury,DavidHumeandothereconomist

23、swroteabouttherelationshipbetweenmonetarychangesandimportantmacroeconomicvariablessuchasproduction,employment,realwages,andrealinterestrates.2.Theysuggestedthateconomicvariablesshouldbedividedintotwogroups:nominalvariablesandrealvariables.Definitionofnominalvariables:variablesmeasuredinmonetaryunits

24、.Definitionofrealvariables:variablesmeasuredinphysicalunits.Definitionofclassicaldichotomy:thetheoreticalseparationofnominalandrealvariables.4.Pricesintheeconomyarenominal(becausetheyarequotedinunitsofmoney),butrelativepricesarereal(becausetheyarenotmeasuredinmoneyterms).Classicalanalysissuggestedth

25、atdifferentforcesinfluencerealandnominalvariables.Changesinthemoneysupplyaffectnominalvariablesbutnotrealvariables.Definitionofmonetaryneutrality:thepropositionthatchangesinthemoneysupplydonotaffectrealvariables.MankysmMbgy時chAnqinptheoF?yardfrom3binrhesto】Sinrfesisau&eFulwaytoexplainIfie-ctrifusioj

26、itl-ial!aebariqeinaunitofmea&iHEiM白止(craunccfaccount)anVelocityandtheQuantityEquationDefinitionofvelocityofmoney:therateatwhichmoneychangeshands.Tocalculatevelocity,wedividenominalGDPbythequantityofmoney.vdocity=nonnalGOfmcney卻旳IfPisthepricelevel(theGDPdeflator),YisrealGDP,andMisthequantityofmoney:v

27、cih*=Rearranging,wegetthequantityequation:枷I/訂疔286?Chapter17/MoneyGrowthandInflationDefinitionofquantityequation:theequationMxV=PxY,whichrelatesthequantityofmoney,thevelocityofmoney,andthedollarvalueoftheeconomysoutputofgoodsandservices.Thequantityequationshowsthatanincreaseinthequantityofmoneymustb

28、ereflectedinoneoftheotherthreevariables.Specifically,thepricelevelmustrise,outputmustrise,orvelocitymustfall.麗紀3Figure3showsnominalGDP,thequantityofmoney(asmeasuredbyM2)andthevelocityofmoneyfortheUnitedStatessinceI960.Itappearsthatvelocityisfairlystable,whilenominalGDPandthemoneysupplyhavegrowndrama

29、tically.Wecannowexplainhowanincreaseinthequantityofmoneyaffectsthepricelevelusingthequantityequation.Thevelocityofmoneyisrelativelystableovertime.Whenthecentralbankchangesthequantityofmoney(M),itwillproportionatelychangethenominalvalueofoutput(PxY).Theeconomysoutputofgoodsandservices(Y)isdeterminedp

30、rimarilybyavailableresourcesandtechnology.Becausemoneyisneutral,changesinthemoneysupplydonotaffectoutput.ThismustmeanthatPincreasesproportionatelywiththechangeinM.Thus,whenthecentralbankincreasesthemoneysupplyrapidly,theresultisahighrateofinflation.CaseStudy:MoneyandPricesduringFourHyperinflationsHy

31、perinflationisgenerallydefinedasinflationthatexceeds50%permonth.ALTERNATIVECLASSROOMEXAMPLE:Supposethat:RealGDP=$5,000Velocity=5Moneysupply=$2,000Pricelevel=2Wecanshowthat:MxV=PxY$2,000 x5=2x$5,000$10,000=$10,000Chapter17/MoneyGrowthandInflation?287Figure4showsdatafromfourclassicperiodsofhyperinflat

32、ionduringthe1920sinAustria,Hungary,Germany,andPoland.Wecanseethat,ineachgraph,thequantityofmoneyandthepricelevelarealmostparallel.TheseepisodesillustratePrinciple#9:Pricesrisewhenthegovernmentprintstoomuchmoney.TheInflationTaxSomecountriesusemoneycreationtopayforspendinginsteadofusingtaxrevenue.Defi

33、nitionofinflationtax:therevenuethegovernmentraisesbycreatingmoney.Theinflationtaxislikeataxoneveryonewhoholdsmoney.iri山Ehatfrtan瞰isanwresubtlefmof(thantest即也rdTrmsof宗擁m(inzoniet詢sales!%etc).JAlmostallhyperinflationsfollowthesamepattern.Thegovernmenthasahighlevelofspendingandinadequatetaxrevenuetopay

34、foritsspending.Thegovernmentsabilitytoborrowfundsislimited.Asaresult,itturnstoprintingmoneytopayforitsspending.Thelargeincreasesinthemoneysupplyleadtolargeamountsofinflation.Thehyperinflationendswhenthegovernmentcutsitsspendingandeliminatestheneedtocreatenewmoney.5.FYI:HyperinflationinZimbabweInthe2

35、000s,Zimbabwefacedoneofhistorysmostextremeexamplesofhyperinflation.Beforetheperiodofhyperinflation,oneZimbabwedollarwasworthabitmorethanoneU.S.dollar.By2009,theZimbabwegovernmentwasissuingnoteswithdenominationsaslargeas10trillionZimbabwedollars(whichwereworthaboutthreeU.S.dollars).TheFisherEffectRec

36、allthattherealinterestrateisequaltothenominalinterestrateminustheinflationrate.This,ofcourse,meansthat:rorinalinrefesticte=嗨i乜飯rate+i吋就;tnrate288?Chapter17/MoneyGrowthandInflationThesupplyanddemandforloanablefundsdeterminestherealinterestrate.Growthinthemoneysupplydeterminestheinflationrate.WhentheF

37、edincreasestherateofgrowthofthemoneysupply,theinflationrateincreases.Thisinturnwillleadtoanincreaseinthenominalinterestrate.DefinitionofFishereffect:theone-for-oneadjustmentofthenominalinterestratetotheinflationrate.TheFishereffectdoesnotholdintheshortruntotheextentthatinflationisunanticipated.Ifinf

38、lationcatchesborrowersandlendersbysurprise,thenominalinterestratewillfailtoreflecttheriseinprices.Figure5showsthenominalinterestrateandtheinflationrateintheU.S.economysince1960.III.TheCostsofInflationA.AFallinPurchasingPower?TheInflationFallacyMostindividualsbelievethatthemajorproblemcausedbyinflati

39、onisthatinflationlowersthepurchasingpowerofapersonsincome.However,aspricesrise,sodoincomes.Thus,inflationdoesnotinitselfreducethepurchasingpowerofincomes.irtout:ojdentsthatpricesii.iolve迥1bj/eisatdseks.iijiesJatJiethis”誹卻Teespaidbysutmars皈曲ohse:MEheh*hmivoriesfeceved吟!:he咄ejs.Alsoemio:studentth就j.c-

40、isrsoftengspayi”cr已跖加tme比B.shoeleOth制CStS血麼訛“林瀕訊Becauseinflationerodesthevalueofmoneythatyoucarryinlocketyoucanavodropinvaluebyholdinglessmoney.ALTERNATIVECLAssROOMEXAMPLE:Realinterestrate=5%Inflationrate=2%Thismeansthatthenominalinterestratewillbe5%+2%=7%.Iftheinflationraterisesto3%,thenominalinter

41、estratewillriseto5%+3%=8%.Chapter17/MoneyGrowthandInflation?289However,holdinglessmoneygenerallymeansmoretripstothebank.Definitionofshoeleathercosts:theresourceswastedwheninflationencouragespeopletoreducetheirmoneyholdings.Thiscostcanbeconsiderableincountriesexperiencinghyperinflation.MenuCostsDefin

42、itionofmenucosts:thecostsofchangingprices.Duringperiodsofinflation,firmsmustchangetheirpricesmoreoften.Relative-PriceVariabilityandtheMisallocationofResourcesBecausepricesofmostgoodschangeonlyonceinawhile(insteadofconstantly),inflationcausesrelativepricestovarymorethantheywouldotherwise.Wheninflatio

43、ndistortsrelativeprices,consumerdecisionsaredistortedandmarketsarelessabletoallocateresourcestotheirbestuse.Inflation-InducedTaxDistortionsLawmakersfailtotakeinflationintoaccountwhentheywritetaxlaws.Thenominalvaluesofinterestincomeandcapitalgainsaretaxed(nottherealvalues).SbudeiKiir.iths兌曲1intrig”i叫

44、,HoxhaiotccisidEre-J迦facttici際Iev.sdoncJfftriertisebeMe印間mi冋ar.Jrealintaeiiisomsaidta湖陽ii耳an(j也即soonriiShatthis斷tetdtodfeif曲她ofsaving,orkrmuiharoftheafter-taxlealntaestrsteurde-differeritinfalienacinardsasisbhfelj畑，Table1showsahypotheticalexampleoftwoindividuals,livingintwocountriesearningthesamerea

45、linterestrate,andpayingthesametaxrate,butoneindividuallivesinacountrywithoutinflationandtheotherlivesinacountrywith8%inflation.Thepersonlivinginthecountrywithinflationendsupwithasmallerafter-taxrealinterestrate.Thisimpliesthathigherinflationwilltendtodiscouragesaving.Apossiblesolutiontothisproblemwo

46、uldbetoindexthetaxsystem.290?Chapter17/MoneyGrowthandInflation扯頁何訕SSRQOMEXAMPLE;damahandMiley鍛1瑞街realrite:raceontheirsm:saccountof3乩愉冊Hamahh?sha刖吩訕AlinfaisnraterwhileFifivesiiacunt?wna10吩nfeticnrate,Bethcountrieshavea2tttaxonie.HinabMileyRealibsIrrSazanrate11-JMsniinali曲町灌斗13Reducediitere韶ueio曲就U出湫憔

47、onandin寵酒ceUMoney茨thei稠粽k錚tweusetomeasureeconomicTtransactions.1.42.Wheninflationoccurs,thevalueofmoneyfalls.Thisalterstheyardstickthatweusetomeasereidmpo鮒“vb伽血dike媲oesferopr<ileysciintyttiaiinbaniKhsThisG.IASpUial減購孤應鷄屈盹用止如襯瞄輸騙佛晶nsofWealth.Example:SamStudenttakesouta$20,000loanat7%interest(nomina

48、l).In10years,theloanwillcomedue.Afterhisdebthascompoundedfor10yearsat7%,Samwillowethebank$40,000.Therealvalueofthisdebtwilldependoninflation.Iftheeconomyhasahyperinflation,wagesandpriceswillrisesomuchthatSammaybeabletopaythe$40,000outofpocketchange.Iftheeconomyhasdeflation,Samwillfindthe$40,000agrea

49、terburdenthanheanticipated.Becauseinflationisoftenhardtopredict,itimposesriskonbothSamandthebankthattherealvalueofthedebtwilldifferfromthatexpectedwhentheloanismade.Inflationisespeciallyvolatileanduncertainwhentheaveragerateofinflationishigh.InflationIsBad,butDeflationMayBeWorseAlthoughinflationhasb

50、eenthenorminrecentU.S.history,from1998to2012Japanexperienceda4-percentdeclineinitsoverallpricelevel.Deflationleadstolowershoeleathercosts,butstillcreatesmenucostsandrelative-pricevariability.Chapter17/MoneyGrowthandInflation?291Deflationalsoresultsintheredistributionofwealthtowardcreditorsandawayfro

51、mdebtors.CaseStudy:TheWizardofOzandtheFreeSilverDebateSomescholarsbelievethatthebookTheWizardofOzwaswrittenaboutU.S.monetarypolicyinthelate19thcentury.From1880to1896,theUnitedStatesexperienceddeflation,redistributingwealthfromfarmers(withoutstandingloans)tobanks.BecausetheUnitedStatesfollowedthegold

52、standardatthistime,onepossiblesolutiontotheproblemwastostarttousesilveraswell.Thiswouldincreasethesupplyofmoney,raisingthepricelevel,andreducetherealvalueofthefarmersdebts.Therehasbeensomedebateovertheinterpretationassignedtoeachcharacter,butitisclearthatthestoryrevolvesaroundthemonetarypolicydebate

53、atthattimeinhistory.Eventhoughthosewhowantedtousesilverweredefeated,themoneysupplyintheUnitedStatesincreasedin1898whengoldwasdiscoveredinAlaskaandsuppliesofgoldwereshippedinfromCanadaandSouthAfrica.Within15years,priceswerebackupandthefarmerswerebetterabletohandletheirdebts.Activity1-TlieInflatioiiFa

54、iryIpe:In：assdeTnsratjnIonics:InfiadsnMatMahneeded:Itai?Iiiik:IOriirunesClasslinutations:Wsrisinc艸sizecPurposeThis貶血代門o徹僦出腔已ffen-dtilancii.AskVe(lasstoccnsdertfeeffectofar.暢ightdatingofpies.feftheneverythrigdoubledripice喃能thyslepi.AsdtiwtMsoldtcrad:lb;卿哋侖瞇論商acar蚯運fcr救腮nwsellsfor觀000,292?Chapter17/Mo

55、neyGrowthandInflationr*nd陶talafi(eszoirJe.Pieii旳ti:rfairysneakstiat-ig-t5idrepaHieS10tillintheirwletwifia制抑b.Hieinfatkn甸eve-toutestheminsirtheirpiggybcnks.0tieptsctejeriin:cwbedo忙nigk,礦址怕此happer?POINTSFORDISCUSSIONthepricesof鍬策ii%doubledo吒nigk,wratwaukbapper:曲THING,Irallpries血掖psredy曲怎肺“dkioreal寵ct醐

56、僦帕Idh號斑：tfiesarrew曲揃gpwer.The;b.is仍iruh“neybin琥卩血nqestsMi？asmuchT恰忙beer代fdatvecravesin卩館Thisisa加皿朮池oJ時:川砂cat*.Ptes忙d:irtreaseitoibthanabillii-rHina(rentalLis遊ofprtEchanqt.試.if猶卩曲即adjustsfejfettiythere,lbeno舊I才酬outheeccnc4ny.Thepra甌ofwu禺ifAcregfigrt.tionrarytiairirthatevertinga-iustssmefly.Someprices

57、adjusttutkiyEidcthasdonotC3aitahneeszcjldnot眈h汩nflataifaiw禺peoplei,culJrdbejilhg衛(wèi)h:ldcash:tdeptshinpaymentHi&帥川i叩easeImn曲enocstccisiiraal?;SOLUTONSTO潘誹pROBLEMS起血訓I也麗和ndDserstrxirii佃on,Fc用吶quizzes：卅-d：，!訟-：i：etiUth:iuu.訃兒u:匕；:wkenuhe0ve?g(tcOUfi爐仏鈿聽粧偽脈礎浙irateieiKfemo巔yihppiyfrOmtytheoryofmoney.Nomina

58、linterestrateswillincreaseperceniiytai5operc甌輛強r,龍卿甜e皿erofpi畫輪顒用礫拠業(yè)qU臨asiPredictedby戯駅tythJo：dramaticallyaswell,aspredictedbytheFishereffect.ThegovernmentmaybeincreasinghereqeO白簞底旃:住in:anie缺5no:keep卬wmrflaioriViillse.Arwre嗎mo嚴y劉Py暮哪c即能曙劑汙Chapter17/MoneyGrowthandInflation?2932/SixcostsonnfldnaieKbtsh

59、cfe莎hericos肢餌menu詛劃;昨加期層印恪醪請“時adiheimisauocafioniofFss3iSpes；l(4)：(MtioE-inducedtaxdistortions;confusionandinconvenience;and(6)arbitraryredistributionsofwealth.Shoeleathercostsarisebecausemoreoften.贏蕊沁”.bludioftheprcblffp.withinflatenis血iributional曲世阿Hinflationcausespeopletospoparesourcesgoigtotheba

60、n!line5petMKfij由毗ir/lafion.cr賢:柚”gironinflabou.sa刖仍in:打已呦逬whenpeoplespendresourceschangingtheirpostedprices.Relative-pricevariabilityoccursbecauseasgeneralpricesrise,afixeddollarpricetranslatesintoadecliningrelativeprice,soherelativepricesofgoodsareconstantlychanging：causingamisallocationofresources