商务统计智慧树知到期末考试答案2024年

商务统计智慧树知到期末考试答案2024年商务统计Aone-tailp-valueistwotimesthesizeofthatforatwo-tailtest.

A:错B:对答案:错Ifadatabatchisapproximatelynormallydistributed,itsnormalprobabilityplotwouldbeS-shaped.

A:对B:错答案:错Thevalueofthesumofsquaresforregression,SSR,canneverbesmallerthan0.0.

A:错B:对答案:对AlphaistheprobabilityofaTypeIerror.

A:错误B:正确答案:正确Thevalueofthesumofsquaresforregression,SSR,canneverbelargerthanthevalueoftotalsumofsquares,SST.

A:错B:对答案:错Thep-valueisusually0.05.

A:对B:错答案:错Thetotalareaunderanynormalcurveisalways1.

A:对B:错答案:对Thelargestvalueinasetofdatais140,andthelowestvalueis70.Iftheresultingfrequencydistributionistohavefiveclassesofequalwidth,theclasswidthwillbe14.

A:错B:对答案:对Ifthenullhypothesisisrejected,thenthealternativeissupported.

A:错误B:正确答案:正确Theverticalspreadofthedatapointsabouttheregressionlineismeasuredbythey-intercept.

A:对B:错答案:错A95%confidenceintervalestimateforapopulationmeanisdeterminedtobe75to85.Iftheconfidencelevelisreducedto80%,theconfidenceintervalforµbecomesnarrower.

A:对B:错答案:对Inordertoestimatewith95%confidenceaparticularvalueofyforagivenvalueofxinasimplelinearregressionproblem,arandomsampleof20observationsistaken.Theappropriatetablevaluethatwouldbeusedis2.101.

A:对B:错答案:对Ajointeventisaneventthathastwoormorecharacteristics.

A:错B:对答案:对Themeanisoneofthemostfrequentlyusedmeasuresofvariability.

A:对B:错答案:错ThereisaninverserelationshipbetweentheprobabilitiesofTypeIandTypeIIerrors.

A:错B:对答案:对Marginalprobabilityistheprobabilitythatagiveneventwilloccur,withnoothereventstakenintoconsideration.

A:对B:错答案:对Thestandarddeviationofthesamplingdistributionofthesamplemeanisalsocalledthecentrallimittheorem.

A:对B:错答案:错Ifthepopulationvariancesarenotequal,theseparatevariancettestfordifferencesintwomeansisappropriate.

A:对B:错答案:对Thenormalapproximationtothebinomialdistributionworksbestwhenthenumberoftrialsislarge,andwhenthebinomialdistributionissymmetrical(likethenormal).

A:错B:对答案:对IfP(A)=0.4andP(B)=0.6,thenAandBmustbecollectivelyexhaustive.

A:错B:对答案:错IfP(A)=0.20,P(B)=0.30andP(A∩B)=0.06,thenAandBare:

A:dependentevents.B:mutuallyexclusiveevents.C:complementaryevents.D:independentevents.答案:independentevents.Asummarymeasurethatiscomputedfromapopulationiscalled:

A:asample.B:astatistic.C:aparameter.D:Both“aparameter.”and“astatistic.”arecorrect,sincetheyarethesame.答案:aparameter.Aregressionlineusing25observationsproducedSSR=118.68andSSE=56.32.Thestandarderrorofestimatewas:

A:1.5648.B:2.1788.C:1.5009.D:2.2716.答案:1.5648Thestandardisedresidualisdefinedas:

A:residualdividedbythestandarderrorofestimate.B:residualdividedbythesquareofthestandarderrorofestimate.C:residualmultipliedbythestandarderrorofestimate.D:residualmultipliedbythesquarerootofthestandarderrorofestimate.答案:residualdividedbythestandarderrorofestimate.Inregressionanalysis,ifthecoefficientofdeterminationis1.0,then:

A:thesumofsquaresforerrormustbe1.0.B:thesumofsquaresforregressionmustbe1.0.C:thesumofsquaresforerrormustbe0.0.D:thesumofsquaresforregressionmustbe0.0.答案:thesumofsquaresforerrormustbe0.0.Whendevelopinganintervalestimateforthedifferencebetweentwosamplemeans,withsamplesizesofn1andn2,

A:n1mustbelargerthann2B:n1andn2canbeofdifferentsizes,C:n1mustbeequalton2D:n1mustbesmallerthann2答案:n1andn2canbeofdifferentsizesApointestimateisdefinedas:

A:asinglevaluethatisthebestestimateofanunknownsamplestatistic.B:theaverageofthepopulationvalues.C:theaverageofthesamplevalues.D:asinglevaluethatisthebestestimateofanunknownpopulationparameter.答案:asinglevaluethatisthebestestimateofanunknownpopulationparameter.AstatisticalmeasureofthestrengthofthelinearrelationshipbetweentworandomvariablesXandYisreferredtoasthe:

A:covariance.B:variance.C:expectedvalue.D:standarddeviation.答案:covarianceThePearsoncoefficientofcorrelationrequals1whenthereis/areno:

A:explainedvariation.B:unexplainedvariation.C:y-interceptinthemodel.D:outliers.答案:unexplainedvariation.Ifthecoefficientofcorrelationis0.90,thepercentageofthevariationinthedependentvariableythatisexplainedbythevariationintheindependentvariablexis:

A:0.90%.B:0.81%.C:81%.D:90%.答案:81%Whichofthefollowingtechniquesisusedtopredictthevalueofonevariableonthebasisofothervariables?

A:Correlationanalysis.B:Coefficientofcorrelation.C:Regressionanalysis.D:Covariance.答案:RegressionanalysisThetestfortheequalityoftwopopulationvariancesisbasedon:

A:thedifferencebetweenthesamplevariancesdividedbythedifferencebetweenthesamplemeans.B:theratioofthetwosamplevariances.C:thedifferencebetweenthetwopopulationvariances.D:thedifferencebetweenthetwosamplevariances.答案:theratioofthetwosamplevariances.TheStudentt-distributionapproachesthenormaldistributionasthe:

A:samplesizedecreases.B:numberofdegreesoffreedomdecreases.C:numberofdegreesoffreedomincreases.D:populationsizeincreases.答案:numberofdegreesoffreedomincreases.Theproducerofacertainmedicineclaimsthattheirbottlingequipmentisveryaccurateandthatthestandarddeviationofalltheirfilledbottlesis0.1ounceorless.Asampleof20bottlesshowedastandarddeviationof0.11.Theteststatistictotesttheclaimis

A:4.85B:20C:400D:22.99答案:22.99Thetwographicaltechniquesweusuallyusetopresentnominal(categorical)dataare:

A:barchartandpiechart.B:barchartandhistogram.C:piechartandogive.D:histogramandogive.答案:barchartandpiechart.Asampleofsize200istobetakenatrandomfromaninfinitepopulation.Giventhatthepopulationproportionis0.60,theprobabilitythatthesampleproportionwillbegreaterthanthe0.58is:

A:0.719.B:0.762.C:0.580.D:0.281.答案:0.719Supposethemeansquaresfortreatmentinaone-wayANOVAare24.4andthemeansquaresforerrorare9.8.Therewerefourtreatmentsand7subjectsreceivedeachtreatment(foratotalof28).ThecalculatedvalueofFis_______.

A:14.6B:34.2C:2.49D:9.8答案:2.49Therelationshipbetweentwonumerical(quantitative)variablesisgraphicallydisplayedasa:

A:histogram.B:scatterdiagram.C:piechart.D:barchart.答案:scatterdiagram.Whichofthefollowingp-valueswillleadustorejectthenullhypothesisifthelevelofsignificanceequals0.05?

A:0.15.B:0.025.C:0.10.D:0.05.答案:0.025Theprobabilitydensityfunctionf(x)ofarandomvariableXthatisnormallydistributediscompletelydeterminedoncethe:

A:meanandvarianceofXarespecified.B:meanandmodeofXarespecified.C:meanandmedianofXarespecified.D:medianandmodeofXarespecified.答案:meanandvarianceofXarespecifiedIfallpossiblesamplesofsizenaredrawnfromaninfinitepopulationwithameanof15andastandarddeviationof5,thenthestandarderrorofthesamplemeanequals1.0onlyforsamplesofsize:

A:75.B:15.C:5.D:25.答案:25Theproducerofacertainbottlingequipmentclaimsthatthevarianceofalltheirfilledbottlesis0.027orless.Asampleof30bottlesshowedastandarddeviationof0.2.Thep-valueforthetestis

A:between0.025to0.05B:0.05C:0.025D:between0.05to0.01答案:between0.025to0.05Whentestingforthedifferencebetweentwopopulationvarianceswithsamplesizesofn1=8andn2=10,thenumberofdegreesoffreedomare:

A:16B:7,9C:8,10D:18答案:7,9Asampleofsizenisselectedatrandomfromaninfinitepopulation.Asnincreases,whichofthefollowingstatementsistrue?

A:Thepopulationstandarddeviationincreases.B:Thestandarderrorofthesamplemeanincreases.C:Thepopulationstandarddeviationdecreases.D:Thestandarderrorofthesamplemeandecreases.答案:ThestandarderrorofthesamplemeandecreasesTheownerofafishmarketdeterminedthattheaverageweightforacatfishis3.2poundswithastandarddeviationof0.8pounds.Acitationcatfishshouldbeoneofthetop2%inweight.Assumingtheweightsofcatfisharenormallydistributed,atwhatweight(inpounds)shouldthecitationdesignationbeestablished?

A:4.84poundsB:1.56poundsC:7.36poundsD:5.20pounds答案:4.84poundsWhichofthefourmethodsofdatacollectionisinvolvedwhenapersonretrievesdatafromanonlinedatabase?

A:surveyingB:experimentationC:publishedsourcesD:observation答案:publishedsourcesAnormallydistributedpopulationwith200elementshasameanof60andastandarddeviationof10.Theprobabilitythatthemeanofasampleof25elementstakenfromthispopulationwillbesmallerthan56is:

A:0.0394.B:0.0228.C:0.0166.D:0.3708.答案:0.0166Theexpectednumberofheadsin100tossesofanunbiasedcoinis:

A:30.B:60.C:40.D:50.答案:50.Iftwoindependentlargesamplesaretakenfromtwopopulations,thesamplingdistributionofthedifferencebetweenthetwosamplemeans

A:canbeapproximatedbyaPoissondistributionB:willhaveameanofoneC:canbeapproximatedbyanormaldistributionD:willhaveavarianceofone答案:canbeapproximatedbyanormaldistributionWhichofthefollowingstatementsaboutthearithmeticmeanisnotalwayscorrect?

A:Halfoftheobservationsareoneithersideofthemean.B:Themeanisameasureofthemiddle(centre)ofadistribution.C:Thevalueofthemeantimesthenumberofobservationsequalsthesumofalloftheobservations.D:Thesumofthedeviationsfromthemeaniszero.答案:HalfoftheobservationsareoneithersideofthemeanAresearcherhasatheorythatthemeanforpopulationAislessthanthemeanforpopulationB.Totestthis,sherandomlysamples36itemsfrompopulationAanddeterminesthatthesampleaverageis38.4.Sherandomlysamples64itemsfrompopulationBanddeterminesthatthesampleaverageis44.3.ThepopulationvarianceforAis72andthepopulationvarianceforBis48.0.Alphais.05.Theobservedz-valueis_______.

A:–5.9B:–0.54C:–3.56D:0.54答案:–3.56Whichofthefollowingsummarymeasuresisaffectedmostbyoutliers?

A:Therange.B:Alltheoptionsarecorrect

C:Theinterquartilerange.D:Themedian.答案:TherangeUsingtheconfidenceintervalwhenconductingatwo-tailtestforthepopulationmeanwedonotrejectthenullhypothesisifthehypothesisedvalueforµ:

A:fallsbetweentheLCLandUCL.B:fallsintherejectionregion.C:istotheleftofthelowerconfidencelimit(LCL).D:istotherightoftheupper