国际经济学AnswersChap02Word文件下载.docx

国际经济学AnswersChap02Word文件下载.docx

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800

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321.Howmuchwouldbedemandedatapriceof6pperkilogram?

Readingofffromthegraph:

atapriceof6pperkg,totalmarketdemandis600000tonnespermonth（oralittleunder）.

2.Assumingthatdemanddoesnotchangefrommonthtomonth,plottheannualmarketdemandforpotatoes.

Theamountdemandedwouldbe12timeshigherateachprice.Ifthescaleofthehorizontalaxiswereunaltered,thecurvewouldshiftwayouttotheright.Asimplewayofshowingthenewcurve,therefore,wouldbetocompressthescaleofthehorizontalaxis.（Ifeachofthenumbersontheaxisweremultipliedby12,thecurvewouldremaininphysicallythesameposition.）

1.DrawTracey’sandDarren’sdemandcurvesforpotatoesononediagram.NotethatyouwillusethesameverticalscaleasinFigure2.1,butyouwillneedaquitedifferenthorizontalscale.

ThisisshowninDiagram2.1.

322.Atwhatpriceistheirdemandthesame?

Thetwocurvescrossatapriceof10pperkgandatademandof10kgpermonth.

3.Whatexplanationscouldtherebeforthequitedifferentshapesoftheirtwodemandcurves?

OneexplanationcouldbethatTraceyisquitehappytoeatrice,pastaorbreadinsteadofpotatoes.Thuswhenthepriceofpotatoesgoesupsheswitchestotheseotherfoods,andswitchestopotatoeswhenthepriceofpotatoescomesdown.Darren,bycontrast,maynotseetheseotherfoodsasclosesubstitutesandthushisdemandforpotatoeswillbelesspricesensitive.（Seesection2.4onelasticity.）

33Doallthesesixdeterminantsofdemandaffectbothanindividual’sdemandandthemarketdemandforaproduct?

Allexceptthedistributionofincome.The（national）distributionofincomesimplyaffectsanindividual’sincomeandthusisnotaseparatedeterminantfromincome.

1.AssumethatinTable2.1thetotalmarketdemandforpotatoesincreasesby20percentateachprice–due,say,tosubstantialincreasesinthepricesofbreadandrice.Plottheoldandthenewdemandcurvesforpotatoes.Isthenewcurveparalleltotheoldone?

SeeDiagram2.2below.Asyoucansee,thecurvesarenotparallel.Aconstantpercentageincreaseinquantitydemandedgivesabiggerandbiggerabsoluteincreaseasquantityincreases.

2.Thepriceofporkrisesandyetitisobservedthatthesalesofporkincrease.Doesthismeanthatthedemandcurveforporkisupwardsloping?

Explain.

Nonotnecessarily.Forexample,thepriceofsubstitutessuchasbeef,chickenorlambmayhaverisenbyalargeramount.Insuchcasesthedemandcurveforporkwillhaveshiftedtotheright.Thusalthoughariseinthepriceofporkwillcauseamovementupalongthisnewdemandcurve,moreporkwillneverthelessbedemandedbecauseporkisnowrelativelycheaperthanthealternatives.

341.CompletethedemandscheduleinTable2:

2uptoapriceof50.

P

Qd

5

10

15

20

25

30

35

40

45

50

9000

8000

7000

6000

5000

4000

3000

2000

1000

0

2.Whatisitaboutequation

（2）thatmakesthedemandcurve（a） 

downwardsloping;

（b） 

astraightline?

（a）Thefactthatthe200Ptermhasanegativesign.ThismeansthatasPrises,soQdfalls.

（b）ThefactthatthereisnoPtoapowerterm.Thecurvethushasaconstantslopeof–1/200

1.Referringtoequation（3）,ifthetermahasavalueof–50 

000andthetermbavalueof0.001,constructademandschedulewithrespecttototalincome（Y）.Dothisforincomesbetween£

100millionand£

300millionat£

50millionintervals.

Y（millions）

150

200

250

300

50000

100000

150000

200000

250000

2.Nowusethisscheduletoplotademandcurvewithrespecttoincome.Commentonitsshape.

Thecurvewillbeanupward-slopingstraightline,crossingthehorizontalaxisat–50000.Itwouldriseby100 

000unitsforeach£

100 

millionriseinnationalincome.（SeeDiagram2.3）.

35（Box2.1）Fromthisequation,calculatewhatwouldhappentothedemandforlambif:

（a）thepriceoflambwentupby10pperkg（at1985prices）.

（b）thepriceofbeefwentupby10pperkg（at1985prices）.

（c）personaldisposableincomeperheadwentupby£

100perannum（at1985prices）.

（a）Thedemandwouldgodownby1.12gramsperpersonperweek（i.e.10–0.112）.

（b）Thedemandwouldgoupby1.25gramsperpersonperweek（i.e.100.125）.

（c）Thedemandwouldgodownby1.98gramsperpersonperweek（i.e.1000.0198）.

（Box2.1）1.HowdoestheintroductionoftheTIMEtermaffecttherelationshipbetweenthedemandforlamband（a）thepriceofbeefand（b）personaldisposableincomeperhead?

（a）Thedemandforlambislesssensitivetoachangeinthepriceofbeefthaninthefirstequation.

（b）Thedemandforlambisslightlymoresensitivetoachangeindisposableincomethaninthefirstequationandtherelationshipisnowapositiveone:

i.e.whenincomerises,thedemandforlambrises..

（Box2.1）2.Islambanormalgoodoraninferiorgood?

Aninferiorgoodinthefirstequationandanormalgoodinthesecond.Inthefirstequation,aspersonaldisposableincomerisessothedemandforlambfalls.Inthesecondequationaspersonaldisposableincomerisessothedemandforlambrises.Thereasonisthat,byintroducingtheTIMEterm,wearenowallowingforthefallindemandforlambovertimeasaresultofashiftintastesawayfrommeat.Inotherwords,thesecondequationallowsustotakethisfactoroutofaccountwhenlookingattheeffectofachangeinthepriceoflambonthedemandforlamb.

（Box2.1）Usethesecondequationtoestimatethedemandforlambin1994,1996and2000.Inwhichofthesethreeyearswastheestimationclosesttotheactualfigure?

Explainthedivergencesintheactualfiguresfromthefiguresderivedfromtheequation.

1994:

Qd=192.3–（0.530301.6）+（0.0738343.0）+（0.02618266）–（7.35229）

=192.3–159.85+25.31+215.74–213.21

=60.29（gramsperpersonperweek）

1996:

Qd=192.3–（0.530296.2）+（0.0738325.6）+（0.02618607）–（7.35231）

=192.3–156.99+24.03+224.64–227.91

=56.07（gramsperpersonperweek）

2000:

Qd=192.3–（0.530310.7）+（0.0738320.1）+（0.02619604）–（7.35235）

=192.3–164.67+23.62+250.66–257.32

=44.59（gramsperpersonperweek）

Theequationmostcloselypredictedtheactualconsumptionin1994:

actualconsumption（54gramspppw）was6gramspppwlessthanpredictedbytheequation.In1996and2000,consumptionwasapproximately10gramspppwmorethanpredicted.ThiscanbeexplainedbyBSE,whichcausedashiftindemandfrombeeftolambintheselatertwoyears.

371.Howmuchwouldbesuppliedatapriceof70pperkilo?

About430000tonnespermonth.

2.DrawasupplycurveforfarmerX.AretheaxesdrawntothesamescaleasinFigure2.4?

ThesupplycurveforfarmerXwillmerelyplottherelevanttwocolumnsfromTable2.3.TheverticalaxiscanbedrawntothesamescaleasinFigure2.4,butadifferentscalewillhavetobeusedforthehorizontalaxis（e.g.tonnesratherthanthousandsoftonnes）.

381.Forwhatreasonsmightthesupplyofpotatoesfall?

Examplesinclude:

•Thecostofproducingpotatoesrises.

•Theprofitabilityofalternativecrops（e.g.carrots）rises.

•Apoorpotatoharvest.

•Farmersexpectthepriceofpotatoestorise（short-runsupplyfalls）.

382.Forwhatreasonsmightthesupplyofleatherrise?

•Thecostofproducingleatherfalls.

•Theprofitabilityofproducingalternativeproductsdecreases.

•Thepriceofbeefrises.

•Along-runningindustrialdisputeinvolvingleatherworkersisresolved.

•Producersexpectthepriceofleathertofall（short-runsupplyincreases）.

39Thisquestionisconcernedwiththesupplyofoilforcentralheating.Ineachcaseconsiderwhetherthereisamovementalongthesupplycurve（andinwhichdirection）orashiftinit（leftorright）.（a）Newoilfieldsstartupinproduction.（b）Thedemandforcentralheatingrises.（c）Thepriceofgasfalls.（d）Oilcompaniesanticipateanupsurgeindemandforcentral-heatingoil.（e）Thedemandforpetrolrises.（f）Newtechnologydecreasesthecostsofoilrefining.（g）Alloilproductsbecomemoreexpensive.

（a）Shiftright.（b）Movementupalong（asaresultofariseinprice）.（c）Movementdownalong（asaresultofafallinpriceresultingfromafallindemandaspeopleswitchtogas-firecentralheating）.（d） 

Shiftleft（ifcompanieswanttoconservetheirstocksinanticipationofapricerise）.（e）Shiftright（moreofagoodinjointsupplyisproduced）.（f）Shiftright.（g）Movementupalong.

1.IfPwasoriginallymeasuredin£

s,whatwouldhappentothevalueofthedtermifPwerenowmeasuredinpence?

Itwouldnowhaveavalueof10.

2.Drawtheschedule（table）andgraphforequation（8）forpricesfrom£

1to£

10.Whatisitintheequationthatdeterminestheslopeofthesupply‘curve’?

Qs

1

2

3

4

5

6

7

8

9

10

1500

2500

3500

4500

5500

6500

7500

8500

9500

10500

Thegraphisanupwardslopingstraightlinecrossingthehorizontalaxisat500units.Theslopeisgivenbythevalueofthedterm:

i.e.theslopeis1/1000（forevery£

1increaseinprice,quantitys