商务统计学（上海大学）知到智慧树章节测试掌握度答案

绪论单元测试1【单选题】(10分)PennyBauer,ChiefFinancialOfficerofHarrisonHaulage,suspectsirregularitiesinthepayrollsystem,andordersaninspectionof‘eachandeverypayrollvoucherissuedsince1January2005’.Fivepercentofthepayrollvoucherscontainedmaterialerrors.Thisisanexampleof________________.A.nominaldataB.nonparametricstatisticsC.inferentialstatisticsD.descriptivestatistics正确答案：D第一章单元测试1【单选题】(10分)MichaelBayley,MarketingDirectorofUniPower’sElectricalDivision,isleadingastudytoidentifyandassesstherelativeimportanceofproductfeatures.MichaeldirectshisstafftodesignasurveyquestionnairefordistributiontoallofUniPower’s954customers.Forthisstudy,thesetof954customersisa________________.A.statisticB.parameterC.sampleD.population正确答案：D2【单选题】(10分)ClaudiaTaylor,DirectorofGlobalIndustrialSalesinMelbourne,isconcernedbyadeterioratingsalestrend.Specifically,thenumberofcustomersisstableat1500buttheyarepurchasinglesseachyear.Sheordersherstafftosearchforcausesofthedownwardtrendbyselectingafocusgroupof40industrialcustomers.Forthisstudy,thesetof40industrialcustomersisa_______.A.populationB.parameterC.sampleD.statistic正确答案：C3【单选题】(10分)Apoliticianwhoisrunningfortheofficeofpremierinastatewith3millionregisteredvoterscommissionsasurvey.Inthesurvey,53.6%ofthe5000registeredvotersinterviewedsaytheyplantovoteforhim.ThepopulationofinterestistheA.5000registeredvotersinterviewed.B.53.6%of,or2680,votersinterviewedwhoplantovoteforhimC.3millionregisteredvotersinthestate.D.46.4%of,or2320,votersinterviewedwhoplannottovoteforhim正确答案：C4【单选题】(10分)SimonArnett,DirectorofHumanResources,isexploringthecausesofemployeeabsenteeismatBuderimBottlingduringthelastoperatingyear(1

January2005to31

December2005).Theaveragenumberofabsencesperemployee,calculatedfromthepersonneldataofallemployees,isa___________________.A.populationB.sampleC.statisticD.parameter正确答案：D5【单选题】(10分)AsummarymeasurethatiscomputedfromasampletodescribeacharacteristicofthepopulationiscalledA.BothAandCarecorrect,sincetheyarethesameB.apopulationC.aparameterD.astatistic正确答案：D6【单选题】(10分)SimonArnett,DirectorofHumanResources,isexploringthecausesofemployeeabsenteeismatBuderimBottlingduringthelastoperatingyear(1

January2005to31

December2005).Personnelrecordsof50employeesareselectedforanalysis.(Theplantemploys250.)Forthisstudy,theaveragenumberdaysabsentforthese50

employeesisa________________.A.statisticB.populationC.sampleD.parameter正确答案：A7【单选题】(10分)DescriptivestatisticsdealswithmethodsofA.summarisingdataB.organisingdata.C.presentingdatainaconvenientandinformativewayD.doingalloftheabove正确答案：D8【单选题】(10分)Whichofthefollowingstatementsisnottrue?A.StatisticalinferenceisusedtodrawconclusionsorinferencesaboutcharacteristicsofpopulationsbasedonsampledataB.Inthelanguageofstatistics,thetermpopulationreferstoagroupofpeopleC.OneformofdescriptivestatisticsusesgraphicaltechniquesD.Oneformofdescriptivestatisticsusesnumericaltechniques正确答案：B9【单选题】(10分)Astudentachievesan82onthefirsttestinastatisticscourse.Fromthis,sheassumesthatheraverageattheendofthesemester(afterothertests)willbeabout82.Thisisanexampleof___________________.A.nonparametricstatisticsB.inferentialstatisticsC.wishfulthinkingD.descriptivestatistics正确答案：B10【单选题】(10分)Whichofthefollowingisnotthegoalofdescriptivestatistics?A.DisplayingaspectsofthecollecteddataB.SummarisingdataC.EstimatingcharacteristicsofthepopulationD.Reportingnumericalfindings正确答案：C第二章单元测试1【单选题】(10分)Ifdataaregroupedintointervalsandthenumberofitemsineachgroupislisted,thiscouldbecalleda_______________.A.frequencydistributionB.stemandleafplotC.ogiveD.histogram正确答案：D2【单选题】(10分)Iftheindividualclassfrequencyisdividedbythetotalfrequency,theresultisthe__________.A.cumulativefrequencyB.stemandleafplotC.midpointfrequencyD.relativefrequency正确答案：D3【单选题】(10分)Acumulativefrequencypolygonisalsocalled_______________.A.afrequencypolygonB.anogiveC.ahistogramD.astemandleafplot正确答案：B4【单选题】(10分)Thenumberofclassintervalsinafrequencydistributionisusuallybetween___________.A.1and25B.5and15C.7and9D.3and5正确答案：B5【单选题】(10分)Oneadvantageofastemandleafplotoverafrequencydistributionisthat__________.A.theclassmidpointsareusedasthestemB.thevaluesoftheoriginaldataareretainedC.itcontainsmoreclassintervalsD.theclassmidpointsareusedastheleaf正确答案：B6【单选题】(10分)Onerulethatmustalwaysbefollowedinconstructingfrequencydistributionsisthat________.A.thewidthofeachclassisequaltotherangeB.thenumberofintervalsmustbeanoddnumberC.eachdatapointcanonlyfallintooneclassD.thenumberofclassesmustbelessthan10正确答案：C7【单选题】(10分)Whichofthefollowingisbesttoshowthepercentageofatotalbudgetthatisspentoneachcategoryofitems?A.stemandleafchartB.histogramC.ogiveD.piechart正确答案：D8【单选题】(10分)Acumulativefrequencydistributionwouldprovide_____________.A.agraphofafrequencydistributionB.arunningtotalofthefrequenciesintheclassesC.theproportionofthetotalfrequencieswhichfallintoeachclassD.averycloudypictureofthefrequencies正确答案：B9【单选题】(10分)Thenumberofphonecallsarrivingataswitchboardeachhourhasbeenrecordedandthefollowingfrequencydistributionhasbeendeveloped.ClassIntervalFrequency20-under403040-under604560-under808080-under10045Whatisthecumulativefrequencyofthethirdclass?A.0.40B.80C.75D.155正确答案：D10【单选题】(10分)Thenumberofphonecallsarrivingataswitchboardeachhourhasbeenrecordedandthefollowingfrequencydistributionhasbeendeveloped.ClassIntervalFrequency20-under403040-under604560-under808080-under10045Whatistheapproximaterangeofthenumberofphonecallsarrivingeachhour?A.200B.100C.20D.80正确答案：D第三章单元测试1【单选题】(10分)SimonArnett,DirectorofHumanResources,isexploringemployeeabsenteeismattheBuderimBottlingduringthelastoperatingyear.Asampleofsixpersonnelrecordsproducedthefollowingdata:0,2,4,7,2,9.Thevarianceofthenumberabsencesperemployeeis____________.A.9.67B.11.6C.3.11D.3.41正确答案：B2【单选题】(10分)JessicaSalas,ManagingDirectorofSalasProducts,isreviewingthewarrantypolicyforhercompany’snewmodelofcarbatteries.Lifetestsperformedonasampleof100batteriesindicated:(1)anaveragelifeof75months,(2)astandarddeviationof5months,and(3)batterylifeisapproximatelynormallydistributed.Approximately68%ofthebatterieswilllastbetween________________.A.65and85monthsB.55and95monthsC.60and90monthsD.70and80months正确答案：D3【单选题】(10分)Theaveragestartingsalaryforgraduatesatauniversityis$25,000withastandarddeviationof$2000.AhistogramofthedatashowstheshapetobeveryerraticsoChebyshev’sTheoremshouldbeused.Howmanyofthegraduateswouldhaveastartingsalarybetween21,000and29,000?A.atleast89%B.atleast95%C.atleast68%D.atleast75%正确答案：D4【单选题】(10分)Thesamplestandarddeviationisfoundbytakingthesquarerootof_______.A.thesamplemeanB.thecoefficientofvariationC.themeanabsolutedeviationD.thesamplevariance正确答案：D5【单选题】(10分)Thenumberofstandarddeviationsthatavalue(X)isaboveorbelowthemeanisthe_______.A.coefficientofvariationB.absolutedeviationC.ZscoreD.interquartilerange正确答案：C6【单选题】(10分)Inahistogram,theproportionofthetotalareathatmustbetotheleftofthemedianis（）A.lessthan0.50ifthedistributionisskewedtotheleftB.between0.25and0.60ifthedistributionissymmetricandunimodalC.exactly0.50.D.morethan0.50ifthedistributionisskewedtotheright正确答案：C7【单选题】(10分)WhichofthefollowingisNOTameasureofcentraltendency?A.varianceB.modeC.medianD.mean正确答案：A8【单选题】(10分)Anothertermforaverageis____________.A.meanB.medianC.modeD.variance正确答案：A9【单选题】(10分)Ifthemeanofadistributionisgreaterthanthemedian,thenthedistributionis____________.A.notskewedB.skewedtotheleftC.symmetricalaboutitsmeanD.skewedtotheright正确答案：D10【判断题】(10分)Themeanisnotaffectedbytheextremevalues.A.对B.错正确答案：B第四章单元测试1【单选题】(10分)Aprocessthatproducesoutcomesiscalled_______.A.populationequivalentB.aresultC.aneventD.anexperiment正确答案：D2【单选题】(10分)WhichofthefollowingisNOTalegitimateprobabilityvalue?A.0.67B.15/16C.4/3D.0.23正确答案：C3【单选题】(10分)Anoutcomeofanexperimentiscalled_______.A.aprobabilityB.aneventC.apriorielementsD.acomplement正确答案：B4【单选题】(10分)Thelistofallelementaryeventsforanexperimentiscalled_______.A.theexhaustivelistB.thepopulationspaceC.theeventunionD.thesamplespace正确答案：D5【单选题】(10分)IfAandBaremutuallyexclusiveeventswithP(A)=0.70,thenP(B)：（）A.cannotbelargerthan0.30B.cannotbedeterminedfromtheinformationgivenC.cantakeanyvaluebetween0and0.70D.cantakeanyvaluebetween0and1正确答案：A6【单选题】(10分)IfaneventisinsetXbutisnotinsetY,whichofthefollowingistrue?A.itisintheunionofXandYB.itisnotintheunionofXandYC.itisintheintersectionofXandYD.itisinboththeunionandintersectionofXandY正确答案：A7【单选题】(10分)Iftheoccurrenceofoneeventdoesnotaffecttheoccurrenceofanotherevent,thenthetwoeventsare_______.A.mutuallyexclusiveB.complementsC.independentD.elementaryevents正确答案：C8【单选题】(10分)LetAbetheeventthatastudentisenrolledinanaccountingcourse,andletSbetheeventthatastudentisenrolledinastatisticscourse.Itisknownthat30%ofallstudentsareenrolledinanaccountingcourseand40%ofallstudentsareenrolledinstatistics.Includedinthesenumbersare15%whoareenrolledinbothstatisticsandaccounting.FindP(S).A.0.15B.0.55C.0.40D.0.30正确答案：C9【单选题】(10分)GivenP(A)=0.40,P(B)=0.50,P(A

B)=0.15.Whichofthefollowingistrue?A.AandBarenotindependentB.AandBareindependentC.AandBaremutuallyexclusiveD.AandBarecollectivelyexhaustive正确答案：A10【单选题】(10分)MeaganDaviesmanagesaportfolioof200commonstocks.Herstaffclassifiedtheportfoliostocksby‘industrysector’and‘investmentobjective’.InvestmentIndustrySectorObjectiveElectronicsAirlinesHealthcareTotalGrowth1001040150Income20201050Total1203050200WhichofthefollowingisNOTtrue?A.AirlinesandHealthcarearecollectivelyexhaustive.B.ElectronicsandHealthcarearemutuallyexclusive.C.GrowthandIncomearecomplementaryevents.D.ElectronicsandGrowtharedependent.正确答案：A第五章单元测试1【单选题】(10分)Variableswhichtakeonvaluesonlyatcertainpointsoveragivenintervalarecalled_______.A.pointvariablesB.valuevariablesC.discreterandomvariablesD.continuousrandomvariables正确答案：C2【单选题】(10分)Avariablethatcantakeonvaluesatanypointoveragivenintervaliscalled_______.A.avaluevariableB.adiscreterandomvariableC.apointvariableD.acontinuousrandomvariable正确答案：D3【单选题】(10分)Youareofferedaninvestmentopportunity.Itsoutcomesandprobabilitiesarepresentedinthefollowingtable.XP(X)–$1000.40$0.20+$1000.40Themeanofthisdistributionis_____________.A.$400B.$200C.–$400D.$0正确答案：D4【单选题】(10分)Youareofferedaninvestmentopportunity.Itsoutcomesandprobabilitiesarepresentedinthefollowingtable.XP(X)–$1000.40$0.20+$1000.40Thestandarddeviationofthisdistributionis_____________.A.$800,000B.–$400C.$663D.$894正确答案：D5【单选题】(10分)Thelong-runaverageormeanofaPoissondistributionisusuallyreferredtoas_______.A.mB.aC.sD.l正确答案：D6【单选题】(10分)ThevarianceofaPoissondistributionisequalto_______.A.l2B.l/2C.lD.正确答案：C7【单选题】(10分)IfXisabinomialrandomwithn

=8andp

=0.6,whatistheprobabilitythatXislessthanorequalto2?A.0.009B.0.041C.0.050D.0.375正确答案：C8【单选题】(10分)IfXisabinomialrandomwithn

=8andp

=0.6,whatistheprobabilitythatXisgreaterthan2?A.0.124B.0.011C.0.991D.0.950正确答案：D9【单选题】(10分)Twenty-fiveitemsaresampled.Eachofthesehasthesameprobabilityofbeingdefective.Theprobabilitythatexactly2ofthe25aredefectivecouldbestbefoundby_______.A.usingthebinomialdistributionB.usingthePoissondistributionC.usingtheexponentialdistributionD.usingthenormaldistribution正确答案：A10【单选题】(10分)Youareofferedaninvestmentopportunity.Itsoutcomesandprobabilitiesarepresentedinthefollowingtable.XP(X)–$1000.40$0.20+$1000.40Whichofthefollowingstatementsistrue?A.Thisdistributionissymmetric.B.Thisisabinomialdistribution.C.Thisdistributionisskewedtotheright.D.Thisdistributionisskewedtotheleft.正确答案：A第六章单元测试1【单选题】(10分)Thenormaldistributionisanexampleof_______.A.abimodaldistributionB.anexponentialdistributionC.acontinuousdistributionD.adiscretedistribution正确答案：C2【单选题】(10分)Thetotalareaunderneathanynormalcurveis_______.A.equalto1B.equaltothemeanC.equaltothevarianceD.equaltothecoefficientofvariation正确答案：A3【单选题】(10分)Theareatotheleftofthemeaninanynormaldistributionis_______.A.equaltothemeanB.equaltothevarianceC.equalto0.5D.equalto1正确答案：C4【单选题】(10分)Foranynormaldistribution,anyvaluelessthanthemeanwouldhavea_______.A.negativevarianceB.negativeprobabilityofoccurringC.negativez-scoreD.positivez-score正确答案：C5【单选题】(10分)Astandardisednormaldistributionhasthefollowingcharacteristics:A.hemeanandvariancearebothequalto1B.themeanandvariancearebothequalto0C.themeanisequalto0andthevarianceisequalto1D.themeanisequaltothevariance正确答案：C6【单选题】(10分)IfXisanormalrandomvariablewithmean80andstandarddeviation5,calculatethez-scoreifX=88.A.-1.6B.1.6C.1.8D.-1.8正确答案：B7【单选题】(10分)SupposeXisanormalrandomvariablewithmean60andstandarddeviation2.Az-scorewascalculatedforanumber,andthez-score

is3.4.Whatisx?A.56.6B.53.2C.63.4D.66.8正确答案：D8【单选题】(10分)LetXbeanormalrandomvariablewithmean20andstandarddeviation4.FindP(16<X<

22).A.0.5328B.0.0328C.0.1498D.0.4672正确答案：A9【单选题】(10分)LetXbeanormalrandomvariablewithmean20andstandarddeviation4.The90thpercentileofXis____________.A.25.126B.20.000C.22.698D.26.579正确答案：A10【单选题】(10分)Az-score

isthenumberof__________thatavalueisfromthemean.A.standarddeviationsB.milesC.unitsD.variances正确答案：A第七章单元测试1【单选题】(10分)Asageneralrule,thenormaldistributionisusedtoapproximatethesamplingdistributionofthesamplemeanonlyifA.npandn(1–p)arebothgreaterthan5B.thesamplesizenissufficientlylargeC.thesamplemeaniscloseto0.50.D.theunderlyingpopulationisnormal正确答案：B2【单选题】(10分)TheeightemployeesoftheArtDepartmentandtheir‘yearsofexperience’arelistedinthefollowingtable.EmployeeABCDEFGHExperience(years)1021115748Ifasampleofthreeemployeesisselectedwithreplacement,thenumberofelementaryoutcomesinthesamplespaceis_______________.A.64B.512C.56D.336正确答案：B3【单选题】(10分)Asamplingdistributionisadistributionof_______________.A.apopulationparameter,suchas,µ.B.apopulationattribute,suchas,employee’sage.C.asamplestatistic,suchas,D.excessprofitstoselectedshareholders.正确答案：C4【单选题】(10分)Thestandarddeviationofasamplingdistributioniscommonlycalled_______.A.theuniformspread.B.statisticalmargin.C.thestandarderror.D.statisticalleverage.正确答案：C5【单选题】(10分)Thecentrallimittheoremstatesthatifn

islargeenough,thedistributionofthesamplemeansis_____________distributedregardlessoftheshapeofthepopulation.A.uniformlyB.approximatelynormallyC.randomlyD.nonrandomly正确答案：B6【单选题】(10分)Accordingtothecentrallimittheorem,themeanofthesamplemeansforagivensizeofsampleisequalto_______.A.thepopulationmeandividedbythesquarerootofnB.zeroC.thepopulationmeanD.thepopulationmeandividedbyn正确答案：C7【单选题】(10分)Increasingthesamplesizecausesthestandarderrorofthemeanto________.A.increaseinvalueB.seekmarketequilibriumC.decreaseinvalueD.destabiliseinvalue正确答案：C8【单选题】(10分)Increasingthesamplesizecausesthesamplingdistributionofto________.A.shifttotherightB.havemoredispersionC.shifttotheleftD.havelessdispersion正确答案：D9【单选题】(10分)Supposeapopulationhasameanof90andastandarddeviationof28.Ifarandomsampleofsize49isdrawnfromthepopulation,theprobabilityofdrawingasamplewithameanofmorethan95is_______.A.0.3944B.0.8944C.0.4286D.0.1056正确答案：D10【单选题】(10分)Suppose40%ofalluniversitystudentshaveacomputerathomeandasampleof64istaken.Whatistheprobabilitythatmorethan30ofthoseinthesamplehaveacomputerathome?A.0.8686B.0.3686C.0.6314D.0.1314正确答案：D第八章单元测试1【单选题】(10分)Whenarangeofvaluesisusedtoestimateapopulationparameter,itiscalled_______.A.anintervalestimateB.arangeestimateC.astatisticalparameterD.apointestimate正确答案：A2【单选题】(10分)CatherineCho,DirectorofMarketingResearchatVitalglowPtyLtd,isevaluatingconsumeracceptanceofanewtoothpastepackage.Herstaffreportthat17%ofarandomsampleof200Darwinhouseholdspreferthenewpackagetoallotherpackagedesigns.IfCatherineconcludesthat17%ofallhouseholdspreferthenewpackage,sheisusinga_______.A.astatisticalparameterB.anintervalestimateC.arangeestimateD.apointestimate正确答案：D3【单选题】(10分)Thez-valueassociatedwithatwo-sided90%confidenceintervalis_______.A.1.96B.1.28C.2.575D.1.645正确答案：D4【单选题】(10分)Supposearandomsampleof36isselectedfromapopulationwithastandarddeviationof12.Ifthesamplemeanis98,the99%confidenceintervaltoestimatethepopulationmeanis_______.A.94.08to101.92B.92.85to103.15C.97.35to98.65D.93.34to102.66正确答案：D5【单选题】(10分)SamGates,MarketingDirectorofMansfieldMotors’ElectricalDivision,isleadingastudytoassesstherelativeimportanceofproductfeatures.Anitemonasurveyquestionnairedistributedto121Mansfieldcustomersaskedthemtoratetheimportanceof‘easeofmaintenance’onascaleof1to10(with1meaning‘notimportant’and10meaning‘highlyimportant’).Hisstaffassembledthefollowingstatistics.EaseofMaintenanceMean7.5PopulationStandardDeviation1.1The90%confidenceintervalforthepopulationmeanratingof‘easeofmaintenance’is_____.A.5.69to9.31B.7.34to7.66C.7.30to7.70D.5.34to9.66正确答案：B6【单选题】(10分)Aresearcherwantstoestimatetheproportionofthepopulationwhichpossessagivencharacteristic.Arandomsampleofsize600istakenresultingin330itemswhichpossessthecharacteristic.Thepointestimateforthispopulationproportionis_______.A.0.60B.0.45C.0.33D.0.55正确答案：D7【单选题】(10分)Thet-distributionissimilartoanormaldistribution.Howeverthet-distributionis_______.A.notsymmetricB.bimodalC.flatterD.discrete正确答案：C8【单选题】(10分)Inordertofindvaluesinthet-distributiontable,youmustconvertthesamplesizeorsizesto_______.A.populationsizesB.z-valuesC.degreesoffreedomD.studentvalues正确答案：C9【单选题】(10分)Ifthedegreesoffreedominat-distributionbecomeverylarge,_______.A.thepopulationsizemustbeverylargeB.thesamplemeanapproacheszeroC.thesamplesizemustbeverysmallD.thet-valuesandthez-valuesarealmostthesame正确答案：D10【单选题】(10分)Infindingaconfidenceintervalforthepopulationmean,thepopulationstandarddeviationshouldbeusedifitisknown.Ifthepopulationstandarddeviationisnotknown,thenitshouldbeestimatedwith_______.A.themeanB.thesamplevarianceC.therangeD.thesamplestandarddeviation正确答案：D第九章单元测试1【单选题】(10分)Thefirststepintestingahypothesisistoestablish_______.A.anindirecthypothesisB.apowerfunctionC.anotrejectancehypothesisandarejectionhypothesisD.anullhypothesisandalternativehypothesis正确答案：D2【单选题】(10分)Considerthefollowingnullandalternativehypotheses.Ho:m<=7Ha:m>6Thesehypotheses_______________.A.arenotmutuallyexclusiveB.areestablishedcorrectlyC.donotreferenceapopulationparameterD.arenotcollectivelyexhaustive正确答案：A3【单选题】(10分)Considerthefollowingnullandalternativehypotheses.Ho:m>=7Ha:m<6Thesehypotheses_______________.A.areestablishedcorrectlyB.arenotcollectivelyexhaustiveC.arenotmutuallyexclusiveD.donotreferenceapopulationparameter正确答案：B4【单选题】(10分)Considerthefollowingnullandalternativehypotheses.Ho:£352Ha:>352Thesehypotheses_______________.A.arenotcollectivelyexhaustiveB.areestablishedcorrectlyC.donotreferenceapopulationparameterD.arenotmutuallyexclusive正确答案：C5【单选题】(10分)Theregionofthedistributioninhypothesistestinginwhichthenullhypothesisisrejectediscalledthe_______.A.notrejectanceregionB.alternativeregionC.rejectionregionD.nullregion正确答案：C6【单选题】(10分)Therejectionandnotrejectanceregionsaredividedbyapointcalledthe_______.A.criticalvalueB.rejectionvalueC.notrejectancevalueD.dividingpoint正确答案：A7【单选题】(10分)TheprobabilityofcommittingaTypeIIerrorisrepresentedby_______.A.aB.bC.1–aD.a/2正确答案：B8【单选题】(10分)JenniferCantu,CustomerServicesManageratTri-NationAutoInsurance,monitorstheclaimsprocessingtimeoftheclaimsdivision.Herstandardincludes‘ameanprocessingtimeof5daysorless’.Eachweek,herstaffchecksforcompliancebyanalysingarandomsampleof60claims.Jennifer’salternativehypothesisis________.A.n=60B.<5C.5D.>5正确答案：D9【单选题】(10分)Themanufacturersofadeodorantclaimthatthemeandryingtimeoftheirproductis,atmost,15minutes.Asampleconsistingof16cansoftheproductwasusedtotestthemanufacturer’sclaim.Theexperimentyieldedameandryingtimeof18minuteswithastandarddeviationof6minutes.Testtheclaimatthe0.05significancelevel.A.Computedteststatistic=2andisgreaterthan1.753,sorejectH0:µ=15.B.Computedteststatistic=2andisgreaterthan1.645,sorejectH0:µ≤15.C.Computedteststatistic=2andisgreaterthan1.96,sorejectH0:µ≤15.D.Computedteststatistic=2andisgreaterthan2.131,sorejectH0:µ≤15.正确答案：A10【单选题】(10分)Whathappenstotherejectionregionifthelevelofsignificanceischangedfrom0.10to0.05?A.itgetssmallerB.itgetslargerC.itdoesnotchange正确答案：A第十章单元测试1【单选题】(10分)Restaurateur,DanielValentine,isevaluatingtwosites,PortDouglasandMissionBeach,forhisnextrestaurant.HewantstoprovethatPortDouglasresidents(population1)dineoutmoreoftenthanMissionBeachresidents(population2).Dennyplanstotestthishypothesisusingarandomsampleof81familiesfromeachtown.Hisnullhypothesisis__________.A.s12<s22B.m1–m2>0C.p1–p2=0D.m1≤m2正确答案：D2【单选题】(10分)Aresearcherwantstoestimatethedifferenceinthemeansoftwopopulations.Arandomsampleof36itemsfromthefirstpopulationresultsinasamplemeanof430.Arandomsampleof49itemsfromthesecondpopulationresultsinasamplemeanof460.Thepopulationstandarddeviationsare120forthefirstpopulationand140forthesecondpopulation.Fromthisinformation,apointestimateofthedifferenceofpopulationmeanscanbecalculatedas_______.A.46B.-30C.-13D.43正确答案：B3【单选题】(10分)Aresearcherwantstoestimatethedifferenceinthemeansoftwopopulations.Arandomsampleof36itemsfromthefirstpopulationresultsinasamplemeanof430.Arandomsampleof49itemsfromthesecondpopulationresultsinasamplemeanof460.Thepopulationstandarddeviationsare120forthefirstpopulationand140forthesecondpopulation.Fromthisinformation,a95%confidenceintervalforthedifferenceinpopulationmeansis_______.A.–102.83to42.43B.–76.53to16.53C.85.44to25.44D.–95.90to35.90正确答案：C4【单选题】(10分)Aresearcherisinterestedintestingtodetermineifthemeanofpopulationoneisgreaterthanthemeanofpopulationtwo.Thenullhypothesisisthatthereisnodifferenceinthepopulationmeans(i.e.thedifferenceiszero).Thealternativehypothesisisthatthereisadifference(i.e.thedifferenceisnotequaltozero).Herandomlyselectsasampleof9itemsfrompopulationoneresultinginameanof14.3andastandarddeviationof3.4.Herandomlyselectsasampleof14itemsfrompopulationtworesultinginameanof11.8andastandarddeviation2.9.Heisusinganalphavalueof.10toconductthistest.Assumingthatthepopulationsarenormallydistributed,thedegreesoffreedomforthisproblemare_______.A.22B.15C.23D.2正确答案：B5【单选题】(10分)Aresearcherwantstoconductabefore/afterstudyon11subjectstodetermineifatreatmentresultsinanydifferenceinscores.Thenullhypothesisisthattheaveragedifferenceiszerowhilethealternativehypothesisisthattheaveragedifferenceisnotzero.Scoresareobtainedonthesubjectsbothbeforeandafterthetreatment.Aftersubtractingtheafterscoresfromthebeforescores,theaveragedifferenceiscalculatedtobe–2.40withasamplestandarddeviationof1.21.Assumethatthedifferencesarenormallydistributedinthepopulation.Thedegreesoffreedomforthistestare_______.A.11B.10C.20D.9正确答案：B6【单选题】(10分)Aresearcherisperformingatwo-tailedrelatedsamples(matchedpairs)t-test.Atotalof12peopleareinthesample,andbeforeandaftermeasuresaretaken.Theobservedt-valueforthisis–1.84.Thelevelofsignificanceis0.05.Thecorrectdecisionisto_______.A.takealargersampleB.usethez-tableinsteadofthet-tableC.rejectthenullhypothesisD.donotrejectthenullhypothesis正确答案：D7【单选题】(10分)StefanIrwin,MarketingManageratClassicMerchandise,isinvestigatingresponseratestoscentedandunscenteddirectmailcatalogues.Iftheresponserateforthescentedcatalogue(population1)ishigher,Mikewilladoptthescentedversion.Hisstaffrandomlyselectstwosamplesof200eachfromthecompany’scustomerdatabase.Onemonthafterthe400testcataloguesweremailed,forty-fiveorders(twenty-fivefromthescentedandtwentyfromtheunscented)werereceivedfromthetestcatalogues.Assuminga=.01,Mike’salternatehypothesisis________________.A.p1–p2>0B.m1–m2=0C.s12<s22D.m1–μ2≠0正确答案：A8【单选题】(10分)CowraConstructionCompanypurchasessteelrodsforitsprojects.Basedonprevioustests,ClarrieCarter,QualityAssuranceManager,hasrecommendedpurchasingrodsfromReddingRods(population1),ratherthanStocktonSteel(population2),sinceRedding’srodshadlessvariabilityinlength.Recently,Stocktonreviseditrodshearingoperation,andClarriehassampledtheoutputsfromRedding’