《商务统计》见面课之答案Word文档下载推荐.docx

《商务统计》见面课之答案Word文档下载推荐.docx

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thenumberofintervalsmustbeanoddnumber

答案:

【adjacentclassesmustnotoverlap】

2、问题:

image.png

areestablishedcorrectly

arenotmutuallyexclusively

arenotcollectivelyexhaustive

donnotreferenceapopulationparameter

【arenotcollectivelyexhaustive】

3、问题:

Whenafalsenullhypothesisisnotrejected,theresearcherhasmadea

typeIIerror.

samplingerror.

powerfulerror.

typeIerror

【typeIIerror.】

4、问题:

【image.png】

5、问题:

Whichofthefollowingisanappropriatenullhypothesis?

6、问题:

Inwhattypeoftestisthevariableofinterestthedifferencebetweenthevaluesoftheobservationsratherthantheobservationsthemselves?

atestfortheequalityofvariancesfrom2independentpopulations

atestforthedifferencebetweenthemeansof2relatedpopulations

atestforthedifferencebetweenthemeansof2independentpopulations

Alloftheabove

【Alloftheabove】

7、问题:

Thetestfortheequalityoftwopopulationvariancesisbasedonthe

ratioofthetwosamplevariances

differencebetweenthetwosamplevariances

differencebetweenthetwopopulationvariances

differencebetweenthesamplevariancesdividedbythedifferencebetweenthesamplemeans

【ratioofthetwosamplevariances】

8、问题:

zero.

-0.5.

0.5

one.

【0.5】

9、问题:

tdistributionwith73degreesoffreedom

tdistributionwith72degreesoffreedom.

tdistributionwith71degreesoffreedom

tdistributionwith70degreesoffreedom.

【tdistributionwith70degreesoffreedom.】

10、问题:

正确理解概率的含义及几种常见的概率统计分布

Giventhefollowinginformation:

Standarddeviation=8Coefficientofvariation=64%Themeanwouldthenbe

12.5

8

0.64

1.25

【12.5】

Fromapopulationof500elements,asampleof225elementsisselected.Itisknownthatthevarianceofthepopulationis900.Thestandarderrorofthemeanisapproximately

1.1022

2

30

1.4847

【1.4847】

Asampleof400observationswillbetakenfromaninfinitepopulation.Thepopulationproportionequals0.8.Theprobabilitythatthesampleproportionwillbegreaterthan0.83is

0.4332

0.9332

0.0668

0.5668

【0.0668】

Aweightedaverageofthevalueofarandomvariable,wheretheprobabilityfunctionprovidesweightsisknownas

aprobabilityfunction

arandomvariable

theexpectedvalue

randomfunction

【theexpectedvalue】

Thestudentbodyofalargeuniversityconsistsof60%femalestudents.Arandomsampleof8studentsisselected.Whatistheprobabilitythatamongthestudentsinthesampleexactlytwoarefemale?

0.0896

0.2936

0.0413

0.0007

【0.0413】

image.pngimage.png

1.431

2.047

3.05

21

【1.431】

Exhibit2Thefollowingrepresentstheprobabilitydistributionforthedailydemandofcomputersatalocalstore.image.png

0.7

0.3

0.4

1.0

【0.7】

IfAandBareindependentevents,then

P（A）mustbeequaltoP（B）

P（A）mustbegreaterthanP（B）

P（A）mustbelessthanP（B）

P（A）mustbeequaltoP（A│B）

【P（A）mustbeequaltoP（A│B）】

Thepurposeofstatisticalinferenceistoprovideinformationaboutthe

samplebaseduponinformationcontainedinthepopulation

populationbaseduponinformationcontainedinthesample

populationbaseduponinformationcontainedinthepopulation

meanofthesamplebaseduponthemeanofthepopulation

【populationbaseduponinformationcontainedinthesample】

Atheoremthatallowsustousethenormalprobabilitydistributiontoapproximatethesamplingdistributionofsamplemeansandsampleproportionswheneverthesamplesizeislargeisknownasthe

approximationtheorem

normalprobabilitytheorem

centrallimittheorem

centralnormalitytheorem

【centrallimittheorem】

相关分析及回归分析

Iftwovariables,XandY,haveastronglinearrelationship,then

TheremayormaynotbeanycausalrelationshipbetweenXandY

XcausesYtohappen

YcausesXtohappen

Noneofthesealternativesiscorrect

【TheremayormaynotbeanycausalrelationshipbetweenXandY】

Inordertotestforthesignificanceofaregressionmodelinvolving14independentvariablesand255observati