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设随机变量X1与X2相互独立，且X1～N(0，1)，X2服从的指数分布，试求：的概率密度；
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设随机变量X服从参数为1的Poisson分布随机变量Y服从参数为2的Poisson分布且X与Y相互独
设随机变量X和Y相互独立且均服从01上的均匀分布则下列随机变量中仍服从某区间上的均匀分布的是
X-Y
X+Y
X
2
2X
或非门的输入变量为X1和X2输出变量为Y使输出变量Y为1的X1和X2的值是
0，0
0，1
1，0
1，1
设随机变量X与Y相互独立且都服从正态分布N01则PmaxXY≥0=______
设连续性随机变量X1与X2相互独立且方差均存在X1与X2的概率密度分别为f1x与f2x随机变量Y1
EY
1
＞EY
2
，DY
1
＞DY
2
EY
1
=EY
2
，DY
1
=DY
2
EY
1
=EY
2
，DY
1
＜DY
2
EY
1
=EY
2
，DY
1
＞DY
2
设总体X～Nμσ2μ已知σ未知X1X2X3X4是X的样本则下列随机变量不是统计量的是
A
B
C
D
设随机变量X1X2Xnn>1独立分布且方差σ2>0记则与X1的相关系数为
-1
O
1
设随机变量X服从正态分布Nμ1随机变量y服从分布X2nXY独立令下列结论成立的是
T～t(n-1)
T～t(n)
T～N(0，1)
F～F(1，n)
设总体X服从正态分布N022而X1X2X15是来自总体X的简单随机样本则随机变量 服从分布参数为．
设F1x与F2x分别为随机变量X1与X2的分布函数为使Fx=aF1x－bF2x是某一随机变量的分布函
a＝3／5，b＝－2／5
a＝2／3，b＝2／3
a＝－1／2，b＝3／2
a＝1／2，b＝－3／2
设XY是两个相互独立且服从正态分布N01的随机变量则随机变量Z=maxXY的数学期望EZ=_____
设随机变量X与Y相互独立且都服从正态分布N01则PmaxXY＞10=______
设X1X2X3是总体X的样本则下列随机变量中是正X的无偏统计量的是
A
B
C
D
设随机变量X服从正态分布Nμ1.x1x2x10是取自总体X的10个样本值在显著性水平为α=0.
设随机变量X1与X2相互独立它们的均值分别为3与4方差分别为1与2则 y=4X1αX2的均值与方差分
E（y）=4
E（y）=20
Var（y）=14
Var（y）=24
Var（y）=15
设随机变量列X1X2Xn相互独立且同分布则X1X2Xn服从辛钦大数定律只要随机变量X1______．
设F1x与F2x分别为随机变量X1与X2的分布函数为使Fx=af1x-bF2x是某一随机变量的分布
A
B
C
D
设随机变量X与Y相互独立且X服从正态分布N01Y在[-13]上服从均匀分布则概率PmaxXY≥0=_
假设随机变量Y服从参数为λ=1的指数分布随机变量 1求X1和X2的联合概率分布 2求EX1+X2
若x1x2x3xn为n个相互独立的随机变量则下列说法正确的是.
x1，x2，x3，…，xn服从正态分布，且分布的参数相同，则
服从正态分布
x1，x2，x3，…，xn服从正态分布，且均值相同，方差不同，则
服从正态分布
只有当x1，x2，x3，…，xn服从正态分布时，其均值
才服从正态分布
无论x1，x2，x3，…，xn服从任何分布，其均值
都服从正态分布
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ForhealthinsurancetheUnitedStateshastakentheroadlesstraveled.TheUnitedStatesistheonlyrichcountrywithoutuniversalhealthinsurance.PeopleintheUnitedStatesspendthemostrelyheavilyontheprivatesectorandobtaincarefromtheworld’smostcomplicateddeliverysystem.WhilesomesupportershaveexpressedsatisfactionifnotprideintheseremarkablequalitiesotherscontendthattheUnitedStatesfacesuniquelimitationsinreforminghealthcare.InherexceptionalbookPartingattheCrossroadsAntoniaMaionicomparestheformationoftheU.S.andCanadianhealth-caresystemsfortheyears1930—1960.TheUnitedStatesandCanadaareoftenconsideredthemostsimilarofWesterndemocracies.Theyshareacommonborderarewealthyandhavefederalgovernment.Theirtradeunionsareonlymoderatelypowerfulandtheirpopulationsarediverseandyoung.Neverthelesstheirheath-insurancesystemsarenearlyopposite.TheUnitedStatesreliesonamixofgovernmentplans.TargetedtotheelderlyandindigentandemploymentbasedplanswhichthegovernmentindirectlysupportsCanadaofferspublichealthinsurancetoallqualifiedresidentwiththeprivatesectorprovidingsupplementaryservicesinsomeprovinces.Labororganizationsbecamestrongadvocatesforhealth-insurancereforminbothcountries.Theirimpactpartiallydependedonpoliticalinstitutionsandhowotheractorsparticularlyorganizedmedicinewieldedthem.Canada’sgovernmentalandelectoralsystemsallowedlabortocooperatewithasocialdemocraticpartyintheSaskatchewanprovincewhichestablishedauniversalprogram.TheSaskatchewanprogramdemonstrateduniversalinsurancefeasibilityspurringthedominantLiberalstointroduceanationaluniversalprogram.IncontrasttheU.S.electoralsystemeffectivelyprecludedthird-partyformationforcingorganizedlabortodiluteitshealth-insurancegoalsbecauseitwasoneofmanyinterestsrepresentedbytheDemocraticParty.Maionisuggeststhateconomicvitalityisimportantforthefutureofbothcountries’systemsbuttheprognosisisuncertain.DespiterecentconcernsabouttheCanadiangovernment’sbudgetaryhealthMaionicontendsthatwidespreadsupportprotectsuniversalinsurance.ConverselyMaioniseemspessimisticaboutoptionsforU.S.universalhealthinsurance.Despiteeconomicbuoyancydissensionwilllikelypreventreforms.AlthoughadevastatingeconmnicdownturnwouldmakehealthfinancedifficultineithercountrytheU.S.systemseemsespeciallyvulnerable.Employment-basedinsuranceandMedicarebothrelyonlabormarketattachment.HighchronicunemploymentcouldresultincoveragelossandfinancialdifficultiesforemployerinsuranceandMedicareswellingtheuninsuredpool.Suchacrisiscouldprovideanopeningforuniversalhealthinsurance.InanycasewhethertheUnitedStatesreliesonthepublicorprivatesectorescalatinghealthexpendituresfigureintobudgetofgovernmentcorporationsandfamiliestheU.S.healthcaresystem’sfuturemaydependonAmericanswillingnesstodevotemoreoftheirnationalincometohealthcare.Thepassageismostlikelytobe______.
Mostoftheidlerichsufferunspeakableboredoraasthepriceoftheirfreedomfromdrudgery.AttimestheymayfindreliefbyhuntingbiggameinAfricabutthenumberofsuchsensationsislimitedespeciallyafteryouthispast.46.Accordinglymoreintelligentrichmenworknearlyashardasiftheywerepoorwhilerichwomenmostlykeepthemselvesbusywithinnumerabletriflesofwhoseearth-shakingimportancetheyarefirmlypersuaded. 47.Workisdesirableasapreventiveofboredomfortheboredomamanfeelswhendoingnecessarythoughuninterestingworkisasnothingincomparisonwiththeboredomhefeelswhenhavingnothingtodo.Withthisadvantageofworkanotherisassociatednamelythatitmakesholidaysmuchmoredeliciouswhentheycome.48.Providedamandoesnothavetoworksohardastoimpairhisvigorheislikelytofindfarmorezestinfreetimethananidlemancouldpossiblyfind. Thesecondadvantageofmostpaidworkandofsomeunpaidworkisthatitgiveschancesofsuecessandopportunitiesforambition.Inmostworksuccessismeasuredbyincomeandwhileourcapitalisticsocietycontinuesthisisinevitable.Itisonlywherethebestworkisconcernedthatthismeasureceasestobethenaturalonetoapply.49.Thedesirethatmenfeeltoincreasetheirincomeisquiteasmuchadesireforsuccessasfortheextracomfortsthatahigherincomecanprocure.Howeverdullworkmaybeitbecomesbearableifitisameansofbuihliugupareputationwhetherintheworldatlargeoronlyinone’sowncircle.Continuityofpurposeisoneofthemostessentialingredientsofhappinessinthelongrunandformostmenthiscomeschieflythroughtheirwork. 50.Thesatisfactionofkillingtimeandofaffordingsomeoutlethowevermodestforambitionbelongstomostworkandissufficienttomakeevenamanwhoseworkisdullhappierontheaveragethanamanwhohasnoworkatall.Butwhenworkisinterestingitiscapableofgivingsatisfactionofafarhigherorderthanmererelieffromtedium.Thekindsofworkinwhichthereissomeinterestmaybearrangedinahierarchy.Ishallbeginwiththosewhichareonlymildlyinterestingandendwiththosethatareworthytoabsorbthewholeenergiesofagreatman. 46
Youslipthekeyintotheignitionandcranktheenginetolife.Butbeforeyouputtheearintogearyoutapakeyonthekeyboardmountedbythesteeringwheelandyourneweste-mailflashesuponthewindscreen.Thisseductivesatyriswhatyougetwhenyoucrossaearandaeomputer.Dubbedthenetworkvehieleornet-mobileitmaysooncometoadrivewaynearyouprobablytheonebelongingtoyourrichneighbor.Inanet-mobileamotoristcouldtapintoaregionalroadsystembutalsotomapoutaroutearoundrush-hourtrafficsnags.Driversandpassengerswillbeabletosendandreceivee-mailtrackthelatestsportsscoresorstockquotessurftheWebandevenplayvideogames.Orsoatleastsayanumberofcomputer-industryfirmssuchasMicrosoftSunIBMandNetseape.Themoderncarisalreadyanelectronicshowcaseonwheels.On-boardmicrocomputersimprovefueleconomyandreduceemissions.Theyoperateanti-lockbrakesystemsandonsomeearsevenregulatethefirmnessoftheshockabsorbers.Butmuchofthetechnologyneededtoaddextraisavailablenow.AprototypenetworkvehicleproducedbyaconsortiumofNetseapeSunIBMandDelcoanautomotiveelectronicsfirmbasedinMichiganwasintroducedattherecentannualcomputerindustryshowinLasVegas.Itnotonlyofferedsuchdesktop-eomputer-likeservicesase-mailbutallowedadrivertousethemwithoutlookingawayfromtheroad.Itwasoperatedbyvoicecommandsandprojecteditsdataontothewindscreenusingthesamesortofhead-updisplaysystemfoundinmodernfighterjets.Membersoftheconsortiumthinkareal-worldnetworkvehiclecouldbeinproductioninaslittleasfouryears.Car-makershavealreadybegunrollingoutsomeofthefeaturesfoundontheseprototypenetmobiles.IfthedriverofaGeneralMotorscarequippedwithitsOn-Starsystemlockshiskeyinthecarforexampleanemergencycentrecantransmitadigitalsignaltounlockthedoors.On-staralsocallsautomaticallyforhelpifanaccidenttriggerstheairbags.ToyotaandGeneralMotorsareamongagrowinglistoffirmsofferingsuchin-earnavigationsystems.AndinEuropeBMWandMercedes-Benzrecentlyintroducednavigationhardwarethatcannotonlyplotoutaroutebutalertadrivertotrafficjams.Thein-carnavigationsystemhasallofthefollowingfunctionsEXCEPT______.
设常数a＞0证明当x＞0时不等式e-xx2-ax+1＜1成立
已知4元齐次线性方程组的解全是4元方程iix1+x2+x3=0的解求齐次方程组i的解
设常数a与b满足则a+36=______
Allmodernhumanoriginatedinsub-SaharanAfricaaccordingtoanewstudyboastedbyitsfoundersasthe"finalblow"againstanopposingviewpoint.Notsofastsaysoneanthropologistwhofindsflawsintheevidence. ThenewstudypublishedintheJuly19issueofthejournalNaturedeliverswhattheresearcherssaycouldbethefinalverdictinsupportofthesinglepoint"OutofAfrica"theory. Manicaandcolleaguestookmultiplemeasurementsofmorethan4500malefossilskullsfrom105populationsaroundtheglobe.TheycombinedtheresultswithdatafromstudiesofglobalgeneticvariationsinhumansfindingthatbothgeneticandskullvariabilitydecreasedwithdistancefromAfrica.SopopulationsinsoutheasternAfricaheldthehighestvariabilitycomparedwithpopulationsinothercountries. Theresultsheldevenwhenthescientistsaccountedforclimatesinceclimateconditionscanleadtochangesinskullfeatures."Inverycoldclimatesyoutendtogenerateaslightlythickerbrowridge.Whetherornotthat’stokeephorribleblizzardsoutofyoureyesIdon’tknow"Amossaid. Paststudiesbasedonskullmorphologyhavebeenweakandhavesupportedbothofthehumanoriginviews. InhisownresearchHawksisfundingthatnaturalselectionhasledtochangesinthousandsofgenesduringonlythepastfewthousandyears. "I’mreallythinkingjusttheoppositeofthispaper"Hawkssaid."Therearedifferencesintheskullbetweenpopulationsincludingtheirvariabilitybutitismostlyduetoveryrecenteffectsandnottheoriginofmodernhumans." "ThemuhiregionalideaisidenticaltotherecentAfricanoriginideaexceptforitspredictionthatEuropeansandAsianswerepartofthesinglepopulationoforiginanddidn’tbecomeextinct." [A]"HumansseemtohavepouredoutofAfricaspreadoutacrosstheworldbutatareallyquiteuniformratesuchthatyougetthislovelygraduallossofdiversity"saidstudyteammemberWilliamAmosoftheUniversityofCambridge. [B]Allmodernhumansoriginatedfromthesameancestorsandtheykeptevolvingasthesocietyadvances.Somespeciesdiedoutbutothersremainedtoliveontheearthwhichisstillimpossibletosolve. [C]Attheendofthedayaresolutiontothe"OutofAfrica"debatemaybeimpossiblehesaid.Mostoftheevidencecanbeinterpretedassupportingbothhuman-originstheories."It’sreallyhardtofindthetwo"Hawkssaid. [D]Thisstudy"addsastronglineofevidencetotheOutofAfricahypothesisusingsuchmorphology"saidpaleontologistWillHarcourt-SmithoftheAmericanMuseumofNaturalHistoryinNewYork.Harcourt-Smithwasnotinvolvedinthecurrentresearch. [E]DebateovertheoriginsofmodernhumanshassimmeredamonganthropologistsforyearswithonetheoryassertingthatHomosapiensmigratedacrosstheworldfromasinglepointinAfrica.TheothertheorystatesthatmultiplepopulationsofHomosapiensindependentlyevolvedfromHomoerectusinregionsbeyondAfrica. [F]TherecentstudywasfundedbytheBiotechnologyandBiologicalSciencesResearchCouncil.Ithasprovidedconclusiveevidenceconcerningtheactualprocessofhumanevolution. [G]"Wehavecombinedourgeneticdatawithnewmeasurementsofalargesampleofskullstoshowdefinitelythatmodernhumansoriginatedfromasingleareainsub-SaharanAfrica"saidleadresearcherAndreaManicaoftheUniversityofCambridge. 41.______42.______43.______44.______45. 44
由于折旧等因素某机器转售价格Pt是时间t周的减函数其中A是机器的最初价格在任何时间t机器开动就能产生的利润则使转售出去总利润最大时机器使用的时间t=______周ln2≈0.693
设随机变量X服从正态分布Nμσ2σ＞0Fx是X的分布函数随机变量Y=FX试求EX+Y
Allmodernhumanoriginatedinsub-SaharanAfricaaccordingtoanewstudyboastedbyitsfoundersasthe"finalblow"againstanopposingviewpoint.Notsofastsaysoneanthropologistwhofindsflawsintheevidence. ThenewstudypublishedintheJuly19issueofthejournalNaturedeliverswhattheresearcherssaycouldbethefinalverdictinsupportofthesinglepoint"OutofAfrica"theory. Manicaandcolleaguestookmultiplemeasurementsofmorethan4500malefossilskullsfrom105populationsaroundtheglobe.TheycombinedtheresultswithdatafromstudiesofglobalgeneticvariationsinhumansfindingthatbothgeneticandskullvariabilitydecreasedwithdistancefromAfrica.SopopulationsinsoutheasternAfricaheldthehighestvariabilitycomparedwithpopulationsinothercountries. Theresultsheldevenwhenthescientistsaccountedforclimatesinceclimateconditionscanleadtochangesinskullfeatures."Inverycoldclimatesyoutendtogenerateaslightlythickerbrowridge.Whetherornotthat’stokeephorribleblizzardsoutofyoureyesIdon’tknow"Amossaid. Paststudiesbasedonskullmorphologyhavebeenweakandhavesupportedbothofthehumanoriginviews. InhisownresearchHawksisfundingthatnaturalselectionhasledtochangesinthousandsofgenesduringonlythepastfewthousandyears. "I’mreallythinkingjusttheoppositeofthispaper"Hawkssaid."Therearedifferencesintheskullbetweenpopulationsincludingtheirvariabilitybutitismostlyduetoveryrecenteffectsandnottheoriginofmodernhumans." "ThemuhiregionalideaisidenticaltotherecentAfricanoriginideaexceptforitspredictionthatEuropeansandAsianswerepartofthesinglepopulationoforiginanddidn’tbecomeextinct." [A]"HumansseemtohavepouredoutofAfricaspreadoutacrosstheworldbutatareallyquiteuniformratesuchthatyougetthislovelygraduallossofdiversity"saidstudyteammemberWilliamAmosoftheUniversityofCambridge. [B]Allmodernhumansoriginatedfromthesameancestorsandtheykeptevolvingasthesocietyadvances.Somespeciesdiedoutbutothersremainedtoliveontheearthwhichisstillimpossibletosolve. [C]Attheendofthedayaresolutiontothe"OutofAfrica"debatemaybeimpossiblehesaid.Mostoftheevidencecanbeinterpretedassupportingbothhuman-originstheories."It’sreallyhardtofindthetwo"Hawkssaid. [D]Thisstudy"addsastronglineofevidencetotheOutofAfricahypothesisusingsuchmorphology"saidpaleontologistWillHarcourt-SmithoftheAmericanMuseumofNaturalHistoryinNewYork.Harcourt-Smithwasnotinvolvedinthecurrentresearch. [E]DebateovertheoriginsofmodernhumanshassimmeredamonganthropologistsforyearswithonetheoryassertingthatHomosapiensmigratedacrosstheworldfromasinglepointinAfrica.TheothertheorystatesthatmultiplepopulationsofHomosapiensindependentlyevolvedfromHomoerectusinregionsbeyondAfrica. [F]TherecentstudywasfundedbytheBiotechnologyandBiologicalSciencesResearchCouncil.Ithasprovidedconclusiveevidenceconcerningtheactualprocessofhumanevolution. [G]"Wehavecombinedourgeneticdatawithnewmeasurementsofalargesampleofskullstoshowdefinitelythatmodernhumansoriginatedfromasingleareainsub-SaharanAfrica"saidleadresearcherAndreaManicaoftheUniversityofCambridge. 41.______42.______43.______44.______45. 42
设f’x在[0+∞上单调减少且证明级数收敛
计算二重积分其中积分区域D是由曲线以及直线x=2围成
设随机变量XY的联合概率密度为讨论随机变量X和Y的相关性和独立性
计算反常积分
设且B=P-1AP求矩阵A的特征值与特征向量
ForhealthinsurancetheUnitedStateshastakentheroadlesstraveled.TheUnitedStatesistheonlyrichcountrywithoutuniversalhealthinsurance.PeopleintheUnitedStatesspendthemostrelyheavilyontheprivatesectorandobtaincarefromtheworld’smostcomplicateddeliverysystem.WhilesomesupportershaveexpressedsatisfactionifnotprideintheseremarkablequalitiesotherscontendthattheUnitedStatesfacesuniquelimitationsinreforminghealthcare.InherexceptionalbookPartingattheCrossroadsAntoniaMaionicomparestheformationoftheU.S.andCanadianhealth-caresystemsfortheyears1930—1960.TheUnitedStatesandCanadaareoftenconsideredthemostsimilarofWesterndemocracies.Theyshareacommonborderarewealthyandhavefederalgovernment.Theirtradeunionsareonlymoderatelypowerfulandtheirpopulationsarediverseandyoung.Neverthelesstheirheath-insurancesystemsarenearlyopposite.TheUnitedStatesreliesonamixofgovernmentplans.TargetedtotheelderlyandindigentandemploymentbasedplanswhichthegovernmentindirectlysupportsCanadaofferspublichealthinsurancetoallqualifiedresidentwiththeprivatesectorprovidingsupplementaryservicesinsomeprovinces.Labororganizationsbecamestrongadvocatesforhealth-insurancereforminbothcountries.Theirimpactpartiallydependedonpoliticalinstitutionsandhowotheractorsparticularlyorganizedmedicinewieldedthem.Canada’sgovernmentalandelectoralsystemsallowedlabortocooperatewithasocialdemocraticpartyintheSaskatchewanprovincewhichestablishedauniversalprogram.TheSaskatchewanprogramdemonstrateduniversalinsurancefeasibilityspurringthedominantLiberalstointroduceanationaluniversalprogram.IncontrasttheU.S.electoralsystemeffectivelyprecludedthird-partyformationforcingorganizedlabortodiluteitshealth-insurancegoalsbecauseitwasoneofmanyinterestsrepresentedbytheDemocraticParty.Maionisuggeststhateconomicvitalityisimportantforthefutureofbothcountries’systemsbuttheprognosisisuncertain.DespiterecentconcernsabouttheCanadiangovernment’sbudgetaryhealthMaionicontendsthatwidespreadsupportprotectsuniversalinsurance.ConverselyMaioniseemspessimisticaboutoptionsforU.S.universalhealthinsurance.Despiteeconomicbuoyancydissensionwilllikelypreventreforms.AlthoughadevastatingeconmnicdownturnwouldmakehealthfinancedifficultineithercountrytheU.S.systemseemsespeciallyvulnerable.Employment-basedinsuranceandMedicarebothrelyonlabormarketattachment.HighchronicunemploymentcouldresultincoveragelossandfinancialdifficultiesforemployerinsuranceandMedicareswellingtheuninsuredpool.Suchacrisiscouldprovideanopeningforuniversalhealthinsurance.InanycasewhethertheUnitedStatesreliesonthepublicorprivatesectorescalatinghealthexpendituresfigureintobudgetofgovernmentcorporationsandfamiliestheU.S.healthcaresystem’sfuturemaydependonAmericanswillingnesstodevotemoreoftheirnationalincometohealthcare.FromthefirstsentencewelearnthattheUnitedStates______.
PartB Directions: Studythefollowingdrawingcarefullyandwriteanessayabout200wordsinwhichyoushould 1describethedrawingbriefly 2interpretitsintendedmeaningand 3giveyourcomment.
Mostoftheidlerichsufferunspeakableboredoraasthepriceoftheirfreedomfromdrudgery.AttimestheymayfindreliefbyhuntingbiggameinAfricabutthenumberofsuchsensationsislimitedespeciallyafteryouthispast.46.Accordinglymoreintelligentrichmenworknearlyashardasiftheywerepoorwhilerichwomenmostlykeepthemselvesbusywithinnumerabletriflesofwhoseearth-shakingimportancetheyarefirmlypersuaded. 47.Workisdesirableasapreventiveofboredomfortheboredomamanfeelswhendoingnecessarythoughuninterestingworkisasnothingincomparisonwiththeboredomhefeelswhenhavingnothingtodo.Withthisadvantageofworkanotherisassociatednamelythatitmakesholidaysmuchmoredeliciouswhentheycome.48.Providedamandoesnothavetoworksohardastoimpairhisvigorheislikelytofindfarmorezestinfreetimethananidlemancouldpossiblyfind. Thesecondadvantageofmostpaidworkandofsomeunpaidworkisthatitgiveschancesofsuecessandopportunitiesforambition.Inmostworksuccessismeasuredbyincomeandwhileourcapitalisticsocietycontinuesthisisinevitable.Itisonlywherethebestworkisconcernedthatthismeasureceasestobethenaturalonetoapply.49.Thedesirethatmenfeeltoincreasetheirincomeisquiteasmuchadesireforsuccessasfortheextracomfortsthatahigherincomecanprocure.Howeverdullworkmaybeitbecomesbearableifitisameansofbuihliugupareputationwhetherintheworldatlargeoronlyinone’sowncircle.Continuityofpurposeisoneofthemostessentialingredientsofhappinessinthelongrunandformostmenthiscomeschieflythroughtheirwork. 50.Thesatisfactionofkillingtimeandofaffordingsomeoutlethowevermodestforambitionbelongstomostworkandissufficienttomakeevenamanwhoseworkisdullhappierontheaveragethanamanwhohasnoworkatall.Butwhenworkisinterestingitiscapableofgivingsatisfactionofafarhigherorderthanmererelieffromtedium.Thekindsofworkinwhichthereissomeinterestmaybearrangedinahierarchy.Ishallbeginwiththosewhichareonlymildlyinterestingandendwiththosethatareworthytoabsorbthewholeenergiesofagreatman. 50
设总体X的概率分布为其中参数θ未知且从总体X中抽取一个容量为8的简单随机样本其8个样本值分别是101-11121试求θ的矩估计值
已知α1=12-1Tα2=1-32Tα3=411-6T若Aα1=02TAα2=52TAα3=-37T则A=______
ForhealthinsurancetheUnitedStateshastakentheroadlesstraveled.TheUnitedStatesistheonlyrichcountrywithoutuniversalhealthinsurance.PeopleintheUnitedStatesspendthemostrelyheavilyontheprivatesectorandobtaincarefromtheworld’smostcomplicateddeliverysystem.WhilesomesupportershaveexpressedsatisfactionifnotprideintheseremarkablequalitiesotherscontendthattheUnitedStatesfacesuniquelimitationsinreforminghealthcare.InherexceptionalbookPartingattheCrossroadsAntoniaMaionicomparestheformationoftheU.S.andCanadianhealth-caresystemsfortheyears1930—1960.TheUnitedStatesandCanadaareoftenconsideredthemostsimilarofWesterndemocracies.Theyshareacommonborderarewealthyandhavefederalgovernment.Theirtradeunionsareonlymoderatelypowerfulandtheirpopulationsarediverseandyoung.Neverthelesstheirheath-insurancesystemsarenearlyopposite.TheUnitedStatesreliesonamixofgovernmentplans.TargetedtotheelderlyandindigentandemploymentbasedplanswhichthegovernmentindirectlysupportsCanadaofferspublichealthinsurancetoallqualifiedresidentwiththeprivatesectorprovidingsupplementaryservicesinsomeprovinces.Labororganizationsbecamestrongadvocatesforhealth-insurancereforminbothcountries.Theirimpactpartiallydependedonpoliticalinstitutionsandhowotheractorsparticularlyorganizedmedicinewieldedthem.Canada’sgovernmentalandelectoralsystemsallowedlabortocooperatewithasocialdemocraticpartyintheSaskatchewanprovincewhichestablishedauniversalprogram.TheSaskatchewanprogramdemonstrateduniversalinsurancefeasibilityspurringthedominantLiberalstointroduceanationaluniversalprogram.IncontrasttheU.S.electoralsystemeffectivelyprecludedthird-partyformationforcingorganizedlabortodiluteitshealth-insurancegoalsbecauseitwasoneofmanyinterestsrepresentedbytheDemocraticParty.Maionisuggeststhateconomicvitalityisimportantforthefutureofbothcountries’systemsbuttheprognosisisuncertain.DespiterecentconcernsabouttheCanadiangovernment’sbudgetaryhealthMaionicontendsthatwidespreadsupportprotectsuniversalinsurance.ConverselyMaioniseemspessimisticaboutoptionsforU.S.universalhealthinsurance.Despiteeconomicbuoyancydissensionwilllikelypreventreforms.AlthoughadevastatingeconmnicdownturnwouldmakehealthfinancedifficultineithercountrytheU.S.systemseemsespeciallyvulnerable.Employment-basedinsuranceandMedicarebothrelyonlabormarketattachment.HighchronicunemploymentcouldresultincoveragelossandfinancialdifficultiesforemployerinsuranceandMedicareswellingtheuninsuredpool.Suchacrisiscouldprovideanopeningforuniversalhealthinsurance.InanycasewhethertheUnitedStatesreliesonthepublicorprivatesectorescalatinghealthexpendituresfigureintobudgetofgovernmentcorporationsandfamiliestheU.S.healthcaresystem’sfuturemaydependonAmericanswillingnesstodevotemoreoftheirnationalincometohealthcare.TheSaskatchewanprograminCanadashowsthat______.
设且B=P-1AP求A100
Youslipthekeyintotheignitionandcranktheenginetolife.Butbeforeyouputtheearintogearyoutapakeyonthekeyboardmountedbythesteeringwheelandyourneweste-mailflashesuponthewindscreen.Thisseductivesatyriswhatyougetwhenyoucrossaearandaeomputer.Dubbedthenetworkvehieleornet-mobileitmaysooncometoadrivewaynearyouprobablytheonebelongingtoyourrichneighbor.Inanet-mobileamotoristcouldtapintoaregionalroadsystembutalsotomapoutaroutearoundrush-hourtrafficsnags.Driversandpassengerswillbeabletosendandreceivee-mailtrackthelatestsportsscoresorstockquotessurftheWebandevenplayvideogames.Orsoatleastsayanumberofcomputer-industryfirmssuchasMicrosoftSunIBMandNetseape.Themoderncarisalreadyanelectronicshowcaseonwheels.On-boardmicrocomputersimprovefueleconomyandreduceemissions.Theyoperateanti-lockbrakesystemsandonsomeearsevenregulatethefirmnessoftheshockabsorbers.Butmuchofthetechnologyneededtoaddextraisavailablenow.AprototypenetworkvehicleproducedbyaconsortiumofNetseapeSunIBMandDelcoanautomotiveelectronicsfirmbasedinMichiganwasintroducedattherecentannualcomputerindustryshowinLasVegas.Itnotonlyofferedsuchdesktop-eomputer-likeservicesase-mailbutallowedadrivertousethemwithoutlookingawayfromtheroad.Itwasoperatedbyvoicecommandsandprojecteditsdataontothewindscreenusingthesamesortofhead-updisplaysystemfoundinmodernfighterjets.Membersoftheconsortiumthinkareal-worldnetworkvehiclecouldbeinproductioninaslittleasfouryears.Car-makershavealreadybegunrollingoutsomeofthefeaturesfoundontheseprototypenetmobiles.IfthedriverofaGeneralMotorscarequippedwithitsOn-Starsystemlockshiskeyinthecarforexampleanemergencycentrecantransmitadigitalsignaltounlockthedoors.On-staralsocallsautomaticallyforhelpifanaccidenttriggerstheairbags.ToyotaandGeneralMotorsareamongagrowinglistoffirmsofferingsuchin-earnavigationsystems.AndinEuropeBMWandMercedes-Benzrecentlyintroducednavigationhardwarethatcannotonlyplotoutaroutebutalertadrivertotrafficjams.Anelectronicshowcaseonwheelsprobablymeans______.
计算累次积分
Mostoftheidlerichsufferunspeakableboredoraasthepriceoftheirfreedomfromdrudgery.AttimestheymayfindreliefbyhuntingbiggameinAfricabutthenumberofsuchsensationsislimitedespeciallyafteryouthispast.46.Accordinglymoreintelligentrichmenworknearlyashardasiftheywerepoorwhilerichwomenmostlykeepthemselvesbusywithinnumerabletriflesofwhoseearth-shakingimportancetheyarefirmlypersuaded. 47.Workisdesirableasapreventiveofboredomfortheboredomamanfeelswhendoingnecessarythoughuninterestingworkisasnothingincomparisonwiththeboredomhefeelswhenhavingnothingtodo.Withthisadvantageofworkanotherisassociatednamelythatitmakesholidaysmuchmoredeliciouswhentheycome.48.Providedamandoesnothavetoworksohardastoimpairhisvigorheislikelytofindfarmorezestinfreetimethananidlemancouldpossiblyfind. Thesecondadvantageofmostpaidworkandofsomeunpaidworkisthatitgiveschancesofsuecessandopportunitiesforambition.Inmostworksuccessismeasuredbyincomeandwhileourcapitalisticsocietycontinuesthisisinevitable.Itisonlywherethebestworkisconcernedthatthismeasureceasestobethenaturalonetoapply.49.Thedesirethatmenfeeltoincreasetheirincomeisquiteasmuchadesireforsuccessasfortheextracomfortsthatahigherincomecanprocure.Howeverdullworkmaybeitbecomesbearableifitisameansofbuihliugupareputationwhetherintheworldatlargeoronlyinone’sowncircle.Continuityofpurposeisoneofthemostessentialingredientsofhappinessinthelongrunandformostmenthiscomeschieflythroughtheirwork. 50.Thesatisfactionofkillingtimeandofaffordingsomeoutlethowevermodestforambitionbelongstomostworkandissufficienttomakeevenamanwhoseworkisdullhappierontheaveragethanamanwhohasnoworkatall.Butwhenworkisinterestingitiscapableofgivingsatisfactionofafarhigherorderthanmererelieffromtedium.Thekindsofworkinwhichthereissomeinterestmaybearrangedinahierarchy.Ishallbeginwiththosewhichareonlymildlyinterestingandendwiththosethatareworthytoabsorbthewholeenergiesofagreatman. 48
设其中fx为连续函数求φ’x
已知A是3阶矩阵αii=123是3维非零列向量若Aαi=iαii=123令α=α1+α2+α3证明αAαA2α线性无关
设在某一时间段内进入某大型超市的顾客人数X服从参数为A的泊松分布且每一顾客购买A种商品的概率为p假定各顾客是否购买A种商品是相互独立的求进入该超市的顾客购买A种商品的人数Y的概率分布及Y的期望EY
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服从正态分布 x1，x2，x3，…，xn服从正态分布，且均值相同，方差不同，则服从正态分布 只有当x1，x2，x3，…，xn服从正态分布时，其均值才服从正态分布 无论x1，x2，x3，…，xn服从任何分布，其均值都服从正态分布
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