statistics1 by keller.docx

statistics1 by keller.docx

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statistics1bykeller

CHAPTER1

WHATISSTATISTICS?

SECTIONS1-4

MULTIPLECHOICEQUESTIONS

Inthefollowingmultiple-choicequestions,pleasecirclethecorrectanswer.

1.Youaskedfiveofyourclassmatesabouttheirheight.Onthebasisofthisinformation,youstatedthattheaverageheightofallstudentsinyouruniversityorcollegeis65inches.Thisisanexampleof:

a.descriptivestatistics

b.statisticalinference

c.parameter

d.population

ANSWER:

b

2.Acompanyhasdevelopedanewcomputersoundcard,buttheaveragelifetimeisunknown.Inordertoestimatethisaverage,200soundcardsarerandomlyselectedfromalargeproductionlineandtestedandtheaveragelifetimeisfoundtobe5years.The200soundcardsrepresentthe:

a.parameter

b.statistic

c.sample

d.population

ANSWER:

c

3.Asummarymeasurethatiscomputedfromasampletodescribeacharacteristicofthepopulationiscalleda

a.parameter

b.statistic

c.population

d.sample

ANSWER:

b

4.Asummarymeasurethatiscomputedfromapopulationiscalleda

a.parameter

b.statistic

c.population

d.sample

ANSWER:

a

5.Whendataarecollectedinastatisticalstudyforonlyaportionorsubsetofallelementsofinterest,weareusinga:

a.sample

b.parameter

c.population

d.statistic

ANSWER:

a

6.Whichofthefollowingisnotthegoalofdescriptivestatistics?

a.Summarizingdata

b.Displayingaspectsofthecollecteddata

c.Reportingnumericalfindings

d.Estimatingcharacteristicsofthepopulation

ANSWER:

d

7.Whichofthefollowingstatementsisnottrue?

a.Oneformofdescriptivestatisticsusesgraphicaltechniques

b.Oneformofdescriptivestatisticsusesnumericaltechniques

c.Inthelanguageofstatistics,populationreferstoagroupofpeople

d.Statisticalinferenceisusedtodrawconclusionsorinferencesaboutcharacteristicsofpopulationsbasedonsampledata

ANSWER:

c

8.Descriptivestatisticsdealswithmethodsof:

a.organizingdata

b.summarizingdata

c.presentingdatainaconvenientandinformativeway

d.Alloftheabove

ANSWER:

d

9.Apoliticianwhoisrunningfortheofficeofgovernorofastatewith4millionregisteredvoterscommissionsasurvey.Inthesurvey,54%ofthe5,000registeredvotersinterviewedsaytheyplantovoteforher.Thepopulationofinterestisthe:

a.4millionregisteredvotersinthestate

b.5,000registeredvotersinterviewed

c.2,700votersinterviewedwhoplantovoteforher.

d.2,300votersinterviewedwhoplannottovoteforher

ANSWER:

a

10.Acompanyhasdevelopedanewbattery,buttheaveragelifetimeisunknown.Inordertoestimatethisaverage,asampleof500batteriesistestedandtheaveragelifetimeofthissampleisfoundtobe225hours.The225hoursisthevalueofa:

a.parameter

b.statistic

c.sample

d.population

ANSWER:

b

11.Theprocessofusingsamplestatisticstodrawconclusionsabouttruepopulationparametersiscalled

a.inferentialstatistics

b.thescientificmethod

c.samplingmethod

d.descriptivestatistics

ANSWER:

a

12.Whichofthefollowingismostlikelyapopulationasopposedtoasample?

a.Respondentstoamagazinesurvey

b.Thefirst10studentscompletingafinalexam

c.Everyfifthstudenttoarriveatthebookstoreonyourcampus

d.RegisteredvotersintheStateofMichigan

ANSWER:

d

13.Researcherssuspectthattheaveragenumberofcreditsearnedpersemesterbycollegestudentsisrising.AresearcheratMichiganStateUniversity（MSU）wishedtoestimatethenumberofcreditsearnedbystudentsduringthefallsemesterof2003atMSU.Todoso,herandomlyselects500studenttranscriptsandrecordsthenumberofcreditseachstudentearnedinthefallterm2003.Hefoundthattheaveragenumberofsemestercreditscompletedwas14.85creditsperstudent.Thepopulationofinteresttotheresearcheris

a.allMSUstudents

b.allcollegestudentsinMichigan

c.allMSUstudentsenrolledinthefallsemesterof2003

d.allcollegestudentsinMichiganenrolledinthefallsemesterof2003

ANSWER:

c

14.ThecollectionandsummarizationofthegraduatedegreesandresearchareasofinterestofthefacultyintheUniversityofMichiganofaparticularacademicinstitutionisanexampleof

a.inferentialstatistics

b.descriptivestatistics

c.aparameter

d.astatistic

ANSWER:

b

15.Thosemethodsinvolvingthecollection,presentation,andcharacterizationofasetofdatainordertoproperlydescribethevariousfeaturesofthatsetofdataarecalled

a.inferentialstatistics

b.thescientificmethod

c.samplingmethod

d.descriptivestatistics

ANSWER:

d

16.Whichofthefollowingismostlikelyaparameterasopposedtoastatistic?

a.Theaveragescoreofthefirsttenstudentscompletinganassignment

b.TheproportionoffemalesregisteredtovoteinKentCounty,Michigan

c.Theaverageheightof100studentsrandomlyselectedfromacommunitycollege

d.TheproportionofcarsstoppedyesterdayonUS131thatwerecitedforspeeding

ANSWER:

b

17.Astudyisunderwayinanationalforesttodeterminetheadultheightofpinetrees.Specifically,thestudyisattemptingtodeterminewhatfactorsaidatreeinreachingheightsgreaterthan50feettall.Itisestimatedthattheforestcontains32,000pinetrees.Thestudyinvolvescollectingheightsfrom500randomlyselectedadultpinetreesandanalyzingtheresults.Thesampleinthestudyis

a.the500randomlyselectedadultpinetrees

b.the32,000adultpinetreesintheforest

c.alltheadultpinetreestallerthan50feet

d.allpinetrees,ofanyageintheforest

ANSWER:

a

18.Theestimationofthepopulationaveragestudentexpenditureoneducationbasedonthesampleaverageexpenditureof1,000studentsisanexampleof

a.inferentialstatistics

b.descriptivestatistics

c.aparameter

d.astatistic

ANSWER:

a

TRUE/FALSEQUESTIONS

19.Whenthepurposeofthestatisticalinferenceistodrawaconclusionaboutapopulation,thesignificancelevel,asameasureofreliability,measureshowfrequentlytheconclusionwillbecorrectinthelongrun.

ANSWER:

F

20.Asummarymeasurethatiscomputedfromasampletodescribeacharacteristicofthepopulationiscalledastatistic.

ANSWER:

T

21.Theconfidencelevelistheproportionoftimesthatanestimatingprocedurewillbewrong.

ANSWER:

F

22.Conclusionsandestimatesaboutapopulationbasedonsampledataarenotalwaysgoingtobecorrect.Forthisreasonmeasuresofreliability,suchasthesignificancelevelandtheconfidencelevel,shouldbebuiltintothestatisticalinference.

ANSWER:

T

23.Auniversityemploys2500facultyandstaff.Toascertainhowtheemployeesfeelregardingahealthinsuranceplan,250oftheemployeesaresurveyed.Theproportionofthe250employeeswhofavorthehealthinsuranceplanisaparameter.

ANSWER:

F

24.Inasampleof400studentsinacollegeofbusiness,120ofthemor30%aremarketingmajors.The30%isanexampleofstatisticalinferenceasopposedtodescriptivestatistics.

ANSWER:

F

25.Twenty-fivepercentofasampleof200tennisplayersindicatedthattheirparentsdidnotplaytennis.Basedonthissample,weestimatethatthe25%figureholdsfortheparentsofallprofessionaltennisplayers.Thisisanexampleofdescriptivestatisticsasopposedtostatisticalinference.

ANSWER:

F

26.Apopulationisthetotalityofitemsorthingsofinterestunderconsideration.

ANSWER:

T

27.Alocalcablesystemusingasampleof800subscribersestimatesthatfortypercentofitssubscriberswatchpremiumchannelatmostfourtimesaweek.Thisisanexampleofstatisticalinferenceasopposedtodescriptivestatistics

ANSWER:

T

28.Astatisticisusuallyunobservablewhileaparameterisusuallyobservable.

ANSWER:

F

29.Statisticalinferenceistheprocessofmakinganestimate,prediction,ordecisionaboutapopulationbasedonsampledata.

ANSWER:

T

30.Asummarymeasurethatiscomputedfromapopulationiscalledaparameter.

ANSWER:

T

31.Asampleistheportionoftheuniversethatisselectedforanalysisandmakinginferencesaboutthepopulationfromwhichthesampleisselected.

ANSWER:

T

32.Asapopulationbecomeslarge,itisusuallybettertoobtainstatisticalinformationfromtheentirepopulation.

ANSWER:

F

33.Astatisticisusuallyusedtoprovideanestimateforausuallyunobservedparameter.

ANSWER:

T

34.Asampleisalwaysagoodrepresentationofthetargetpopulation.

ANSWER:

F

35.Estimatingcharacteristicsofthepopulationisthemaingoalofdescriptivestatistics.

ANSWER:

F

STATISTICALCONCEPTS&APPLIEDQUESTIONS

36.Instatistics,whatnamedowegivetoanumericalcharacteristicofasample?

ANSWER:

Statistic

37.Instatistics,whatnamedowegivetoanumericalcharacteristicofapopulation?

ANSWER:

Parameter

38.Amanufacturerofchildrentoysclaimsthatlessthan3%ofhisproductsaredefective.When500toysweredrawnfromalargeproductionrun,5%werefoundtobedefective.

a.Whatisthepopulationofinterest?

b.Whatisthesample?

c.Whatistheparameter?

d.Whatisthestatistic?

e.Doesthevalue3%refertotheparameterorthestatistic?

Why?

f.Doesthevalue5%refertotheparameterorthestatistic?

Why?

g.Explainbrieflyhowthestatisticcanbeusedtomakeinferencesabouttheparametertotesttheclaim.

ANSWER:

a.Thecompleteproductionrunoftoys

b.The500toysdrawnfromtheproductionrun

c.Proportionoftheproductionruntoysthataredefective

d.Proportionofsampletoysthataredefective

e.Parameter;sinceitisasummarymeasurethatiscomputedfromthepopulation

f.Statistic;sinceitisasummarymeasurethatiscomputedfromthesample

g.Sincethesampleproportionismorethan3%,weconcludethattheclaimisfalse.

39.The