statistics21 by kellerWord文档格式.docx

statistics21 by kellerWord文档格式.docx

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a.drawnfromnormalpopulations

b.drawnfrommatchedpairsexperiment

c.independent

d.largerthan30

c

3.TheWilcoxonranksumteststatisticTisapproximatelynormallydistributedwheneverthesamplesizesarelargerthan:

a.10

b.15

c.20

d.25

a

4.AWilcoxonranksumtestforcomparingtwopopulationsinvolvestwoindependentsamplesofsizes5and7.Thealternativehypothesisisstatedas:

Thelocationofpopulation1isdifferentfromthelocationofpopulation2.Theappropriatecriticalvaluesatthe5%significancelevelare:

a.20and45

b.22and43

c.33and58

d.35and56

5.Considerthefollowingtwoindependentsamples:

SampleA:

1617192247

SampleB:

2731343740

Thevalueoftheteststatisticforaleft-tailWilcoxonranksumtestis:

a.6

b.20

c.35

d.55

b

6.Anonparametricmethodtocomparetwopopulations,whenthesamplesareindependentandthedataareeitherordinalorinterval,andwherethenormalityrequirementnecessarytoperformtheparametrictestisnotsatisfied,isthe:

a.Wilcoxonranksumtest

b.signtest

c.Wilcoxonsignedranksumtest

d.equal-variancet-testof

7.Statisticalmethodsthatrequirefewassumptions,ifany,aboutthepopulationdistributionareknownas:

a.parametrictechniques

b.nonparametrictechniques

c.freeagenttechniques

d.Alloftheabove

8.Whichofthefollowingstatementsaboutnonparametrictestsisfalse?

a.Wecansafelyemploynonparametrictestsevenwhenweknownothingatallaboutthepopulationsfromwhichsampledataarebeingdrawn

b.Wecanconductnonparametrictestswithnominaldata

c.Wecanconductnonparametrictestswithordinaldata

d.Wecanonlyconductnonparametrictestswithdataofahigherorderthannominalorordinal

9.Whichofthefollowingstatementsisfalse?

a.Wecanconductnonparametrictestsevenwithnominalandordinaldata

b.Whenparametricassumptionsarevalidand,therefore,eithertypeoftestcouldbeused,nonparametrictestsarelesspowerfulthanparametrictests

c.Givensamplesizeandspecifiedsignificancelevel

theprobabilityofaTypeIIerror

islargerforanonparametrictest

d.Usinganonparametrictestwhenwecouldemployaparametrictestcanbelessefficient:

Anonparametrictestoftentendstoignoreavailablesampleinformation-forexample,byfocusingonlyonthedirectionsratherthanthesizesofobserveddifferences.

10.Considerthefollowingtwoindependentsamples:

151718

14161919202223

Thevalueoftheteststatisticforaright-tailWilcoxonranksumtestis:

a.3

b.7

c.11

d.44

11.Thenonparametrictestsdiscussedinyourbook（Wilcoxonranksumtest,signtest,Wilcoxonsignedranksumtest,Kruskal-WallistestandFriedmantest）allrequirethattheprobabilitydistributionsbe:

a.identicalexceptwithrespecttolocation

b.identicalexceptwithrespecttospread（variance）

c.identicalexceptwithrespecttoshape（distribution）

d.differentwithrespecttolocation,spread,andshape

12.Statisticalmethodsthatrequire,amongotherassumptions,thatthepopulationsbenormallydistributedareknownas:

a.distribution-freetechniques

c.parametrictechniques

d.both（a）and（b）arecorrect

13.InaWilcoxonranksumtest,thetwosamplesizesare4and6,andthevalueoftheWilcoxonteststatisticisT=20.Ifthetestisatwo-tailandthelevelofsignificanceis

then:

a.thenullhypothesiswillberejected

b.thenullhypothesiswillnotberejected

c.thealternativehypothesiswillnotberejected

d.notenoughinformationhasbeengiventoanswerthisquestion

14.ComparingtheoutputofstrawberriesgrownonplotsusingfertilizerAwiththatgrownonotherwiseidenticalplotsusingfertilizerB,inordertomakeageneralassessmentofrelativefertilizereffectiveness,maywellcallfora

a.Friedmantest

b.Kruskal-Wallistest

c.Wilcoxonrank-sumtest

d.Spearmanrankcorrelationtest

15.AWilcoxonranksumtestforcomparingtwopopulationsinvolvestwoindependentsamplesofsizes15and20.Theun-standardizedteststatistic（thatistheranksum）isT=210.Thevalueofthestandardizedteststatisticzis:

a.14.0

b.10.5

c.6.0

d.–2.0

16.Theappropriatemeasureofcentrallocationofordinaldataisthe:

a.mean

b.median

c.mode

17.YouareperformingtheWilcoxonrank-sumtest.The13ththrough15thvaluesinanorderedarrayofpooledsampledataallequal$180（whilethe12thvalueislessandthe16thvalueismore）.Theappropriateranksforthethree$180valuesare

a.13,14,15

b.14,14,14

c.12.5,13,14.5

d.12.5,13,15

18.InanormalapproximationtotheWilcoxonranksumtest,thestandardizedteststatisticiscalculatedasz=1.80.Foratwo-tailtest,thep-valueis:

a.0.0359

b.0.4641

c.0.2321

d.0.0718

ANSWER:

19.Whichofthefollowingwillneverbearequiredconditionofanonparametrictest?

a.Dataareordinal

b.Dataareinterval

c.Thesamplesaredrawnfromnormallydistributedpopulations

d.Thepopulationsbeingcomparedareidenticalinspreadandshape

20.AnonparametricmethodthatisequivalenttotheWilcoxonranksumtestisthe:

a.Wilcoxonsignedranksumtest

b.Friedmantest

c.Kruskal-Wallistest

d.Mann-Whitneytest

21.Considerthefollowingdataset:

2.2,2.3,2.3,2.5,2.6,2.7,2.8,2.8,2.8,2.9,3.1,3.2,and3.5.Therankassignedtothethreeobservationsofvalue2.8is:

c.8

d.9

22.TheWilcoxonranksumtest（likemostofthenonparametrictestspresentedinyourbook）actuallyteststodeterminewhetherthepopulationdistributionshaveidentical:

a.locations

b.spreads（variances）

c.shapes

23.Inferentialproceduresthatarefreefromrestrictiveassumptionsaboutthesampledpopulationsareknownas

a.Distribution-freetests（becausenoassumptionaboutthenatureofthepopulationdistributionisbeingmade）.

b.Distribution-freetests（becausenoassumptionaboutthenatureofthesamplingdistributionsofteststatisticsisbeingmade）.

c.Parametrictests

d.Alloftheabove

24.TousetheWilcoxonRankSumTestasatestforlocation,wemustassumethat

a.theobtaineddataareeitherordinalorintervalwherethenormalityrequirementnecessarytoperformtheequal-variancesttestof

isunsatisfied

b.bothsamplesarerandomlyandindependentlydrawnfromtheirrespectivepopulations

c.bothunderlyingpopulationsfromwhichthesamplesweredrawnareequivalentinshapeanddispersion

25.WhichofthefollowingcorrectlydescribestheWilcoxonrank-sumtest?

a.Itisanonparametrictestbasedontwoindependentsimplerandomsamples

b.Itisdesignedtodeterminewhethertherelativefrequencydistributionsoftwostatisticalpopulationsofcontinuousvaluesareidenticaltoordifferentfromoneanother

c.Itisequivalenttoaparametrict-testofthedifferencebetweentwomeans.

d.Alloftheabove.

ANSWER:

26.ThefirststepinaWilcoxonranksumtestistocombinethedatavaluesinthetwosamplesandassignarankof1tothe:

a.smallestobservation

b.middleobservation

c.largestobservation

d.observationthatoccursmostfrequently

TRUE/FALSEQUESTIONS

27.Aparametrictestisahypothesistestthatdependsoncertainspecificassumptionsabouttheprobabilitydistributionofpopulationvaluesorthesizesofpopulationparameters.

T

28.Nonparametrictestsaremethodsofinferencethatmakenoassumptionswhatsoeveraboutthenatureofunderlyingpopulationdistributionsortheirparameters.

29.Anonparametrictestisonethatmakesnoassumptionsaboutthespecificshapeofthepopulationfromwhichasampleisdrawn.

30.Nonparametricproceduresareoften,andperhapsmoreaccurately,calledfree-agentstatistics.

F

31.AWilcoxonranksumtestforcomparingtwoindependentsamplesinvolvestwosamplesofsizes6and9.Thealternativehypothesisisthatthelocationofpopulation1istotheleftofthelocationofpopulation2.Usinga0.05significancelevel,theappropriatecriticalvaluesare31and65.

32.InaWilcoxonranksumtestforindependentsamples,thetwosamplesizesare4and6,andthevalueoftheWilcoxonteststatisticisT=25.Ifthetestisatwo-tailandthelevelofsignificanceis0.05,thenthenullhypothesiswillberejected.

33.AWilcoxonranksumtestforcomparingtwopopulationsinvolvestwoindependentsamplesofsizes15and20.Ifthevalueofun-standardizedteststatisticisT=225,thenthevalueofthestandardizedteststatisticisz=–1.50.

34.Statisticalteststhatarenotverysensitivetoerrorsinassumptionsarecalledparametrictests.

35.Nonparametrictestsareoftenmoreefficientthanparametrictests.

36.Thestatisticalmethodsdiscus