Ch.12 InferenceonCategoricalData
12.1 Goodnesso
f
FitTest
1 Performagoodnessoffittest.
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
Provideanappropriateresponse.
1) Determinetheexpectedcountsforeachoutcome.
n=600
pi0.25 0.05 0.35 0.35
ExpectedCounts
A)
pi0.25 0.05 0.35 0.35
ExpectedCounts 150 30 210 210
B)
pi0.25 0.05 0.35 0.35
ExpectedCounts 25 5 35 35
C)
pi0.25 0.05 0.35 0.35
ExpectedCounts 154 28 211 207
D)
pi0.25 0.05 0.35 0.35
ExpectedCounts 1500 300 2100 2100
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
2) Amultinomialexperimentwithk=4cellsandn=300producedthedatashowninthefollowingtable.
Cell
1234
ni65 69 80 86
Dothesedataprovidesufficientevidencetocontradictthenullhypothesisthatp1=0.20,p2=0.20,
p3=0.30,andp4=0.30?Testusingα=0.05.
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
3) Manytrackhurdlersbelievethattheyhaveabetterchanceofwinningiftheystartintheinsidelanethatis
closesttothefield.Forthedatabelow,thelaneclosesttothefieldisLane1,thenextlaneisLane2,andsoon
untiltheoutermostlane,Lane6.Thedataliststhenumberofwinsfortrackhurdlersinthedifferentstarting
positions.Calculatethechisquareteststatisticχ2totesttheclaimthattheprobabilitiesofwinningarethe
sameinthedifferentpositions.Useα=0.05.Theresultsarebasedon240wins.
StartingPosition 123456
NumberofWins 33 50 44 32 36 45
A) 6.750 B) 9.326 C) 12.592 D) 15.541
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4) Manytrackhurdlersbelievethattheyhaveabetterchanceofwinningiftheystartintheinsidelanethatis
closesttothefield.Forthedatabelow,thelaneclosesttothefieldisLane1,thenextlaneisLane2,andsoon
untiltheoutermostlane,Lane6.Thedataliststhenumberofwinsfortrackhurdlersinthedifferentstarting
positions.Findthecriticalvalueχ 2
0totesttheclaimthattheprobabilitiesofwinningarethesameinthe
differentpositions.Useα=0.05.Theresultsarebasedon240wins.
StartingPosition 123456
NumberofWins 45 36 32 33 44 50
A) 11.070 B) 9.236 C) 15.086 D) 12.833
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
5) Manytrackhurdlersbelievethattheyhaveabetterchanceofwinningiftheystartintheinsidelanethatis
closesttothefield.Forthedatabelow,thelaneclosesttothefieldisLane1,thenextlaneisLane2,andsoon
untiltheoutermostlane,Lane6.Thedataliststhenumberofwinsfortrackhurdlersinthedifferentstarting
positions.Testtheclaimthattheprobabilitiesofwinningarethesameinthedifferentpositions.Useα=0.05.
Theresultsarebasedon240wins.
StartingPosition 123456
NumberofWins 32 44 36 33 45 50
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
6) Acompanywantstodetermineifitsemployeeshaveanypreferenceamong5differenthealthplanswhichit
offerstothem.Asampleof200employeesprovidedthedatabelow.Calculatethechi squareteststatisticχ2to
testtheclaimthattheprobabilitiesshownopreference.Useα=0.01.
Plan 12345
Employees 65 32 18 55 30
A) 37.45 B) 45.91 C) 48.91 D) 55.63
7) Acompanywantstodetermineifitsemployeeshaveanypreferenceamong5differenthealthplanswhichit
offerstothem.Asampleof200employeesprovidedthedatabelow.Findthecriticalvalueχ2
0totesttheclaim
thattheprobabilitiesshownopreference.Useα=0.01.
Plan 12345
Employees 30 55 32 18 65
A) 13.277 B) 9.488 C) 11.143 D) 14.860
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
8) Acompanywantstodetermineifitsemployeeshaveanypreferenceamong5differenthealthplanswhichit
offerstothem.Asampleof200employeesprovidedthedatabelow.Testtheclaimthattheprobabilitiesshow
nopreference.Useα=0.01.
Plan 12345
Employees 32 18 55 65 30
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MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
9) Ateacherfiguresthatfinalgradesinthechemistrydepartmentaredistributedas:A,25%;B,25%; C,40%;
D,5%;F,5%.Attheendofarandomlyselectedsemester,thefollowingnumberofgradeswererecorded.
Calculatethechisquareteststatisticχ2todetermineifthegradedistributionforthedepartmentisdifferent
thanexpected.Useα=0.01.
Grade ABCDF
Number 42 36 60 14 8
A) 5.25 B) 6.87 C) 0.6375 D) 4.82
10) Ateacherfiguresthatfinalgradesinthechemistrydepartmentaredistributedas:A,25%;B,25%; C,40%;
D,5%;F,5%.Attheendofarandomlyselectedsemester,thefollowingnumberofgradeswererecorded.Find
thecriticalvalueχ 2
0todetermineifthegradedistributionforthedepartmentisdifferentthanexpected.Useα
=0.01.
Grade ABCDF
Number 36 42 60 814
A) 13.277 B) 15.086 C) 9.488 D) 7.779
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
11) Ateacherfiguresthatfinalgradesinthechemistrydepartmentaredistributedas:A,25%;B,25%; C,40%;
D,5%;F,5%.Attheendofarandomlyselectedsemester,thefollowingnumberofgradeswererecorded.
Determineifthegradedistributionforthedepartmentisdifferentthanexpected.Useα
=0.01.
Grade ABCDF
Number 36 42 60 14 8
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
12) Aspinnerismountedonapieceofcardboarddividedintosixareasofequalsize.Eachofthesixareasisa
differentcolor(blue,yellow,red,green,whiteandorange).Whenthespinnerisspun,eachcolorshouldbe
selectedbythespinnerapproximately1
6ofthetime.Astudentsuspectsthatacertainspinnerisdefective.The
suspectedspinnerisspun90times.Theresultsareshownbelow.Calculatethechi squareteststatisticχ2to
testthestudentʹsclaim.Useα=0.10.
Color Blue Yellow Red Green White Orange
Frequency 15 12 11 17 19 16
A) 3.067 B) 2.143 C) 5.013 D) 4.312
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13) Aspinnerismountedonapieceofcardboarddividedintosixareasofequalsize.Eachofthesixareasisa
differentcolor(blue,yellow,red,green,whiteandorange).Whenthespinnerisspun,eachcolorshouldbe
selectedbythespinnerapproximately1
6ofthetime.Astudentsuspectsthatacertainspinnerisdefective.The
suspectedspinnerisspun90times.Theresultsareshownbelow.Findthecriticalvalueχ2
0totestthe
studentʹsclaim.Useα=0.10.
Color Blue Yellow Red Green White Orange
Frequency 12 11 16 19 17 15
A) 9.236 B) 1.610 C) 10.645 D) 11.071
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
14) Aspinnerismountedonapieceofcardboarddividedintosixareasofequalsize.Eachofthesixareasisa
differentcolor(blue,yellow,red,green,whiteandorange).Whenthespinnerisspun,eachcolorshouldbe
selectedbythespinnerapproximately1
6ofthetime.Astudentsuspectsthatacertainspinnerisdefective.The
suspectedspinnerisspun90times.Theresultsareshownbelow.Testthestudentʹsclaim.Useα
=0.10.
Color Blue Yellow Red Green White Orange
Frequency 12 11 17 16 19 15
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
15) Arandomsampleof160carpurchasesareselectedandcategorizedbyage.Theresultsarelistedbelow.The
agedistributionofdriversforthegivencategoriesis18%fortheunder26group,39%forthe26 45group,31%
forthe4565group,and12%forthegroupover65.Calculatethechisquareteststatisticχ2totesttheclaim
thatallageshavepurchaseratesproportionaltotheirdrivingrates.Useα
=0.05.
Age Under26 2645 4665 Over65
Purchases 66 39 25 30
A) 75.101 B) 85.123 C) 101.324 D) 95.431
16) Arandomsampleof160carpurchasesareselectedandcategorizedbyage.Theresultsarelistedbelow.The
agedistributionofdriversforthegivencategoriesis18%fortheunder26group,39%forthe2645group,31%
forthe4565group,and12%forthegroupover65.Findthecriticalvalueχ2
0totesttheclaimthatallages
havepurchaseratesproportionaltotheirdrivingrates.Useα=0.05.
Age Under26 2645 4665 Over65
Purchases 66 39 25 30
A) 7.815 B) 6.251 C) 11.143 D) 9.348
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
17) Arandomsampleof160carpurchasesareselectedandcategorizedbyage.Theresultsarelistedbelow.The
agedistributionofdriversforthegivencategoriesis18%fortheunder26group,39%forthe2645group,31%
forthe4665group,and12%forthegroupover65.Testtheclaimthatallageshavepurchaserates
proportionaltotheirdrivingrates.Useα=0.05.
Age Under26 2645 4665 Over65
Purchases 66 39 25 30
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18) Theresultsofarecentnationalsurveyreportedthat70%ofAmericansrecycleatleastsomeofthetime.Aspart
oftheirfinalprojectinstatisticsclass,NaylaandRobertosurvey5randomstudentsoncampusandaskthemif
theyrecycleatleastsomeofthetime.Theythenrepeatthisexperiment1000times.Theresultsoftheirresearch
areshownbelow.
X(numberwhorecycleoutof5) 012345
Frequency 227 139 305 358 169
IsthereevidencetosupportthebeliefthattherandomvariableX,thenumberofstudentsoutof5whorecycle
atleastsomeofthetime,isabinomialrandomvariablewithp=0.7attheα=0.05level?
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
19) Asthenumberofthedegreesoffreedomincreases,theχ2distribution
A)
b
ecomesmoresymmetric.
B)
b
ecomeslesssymmetric.
C) doesnotchangeshapeasthedegreesoffreedomchange.
D)
b
ecomesexponential.
20) A__________________testisaninferentialprocedureusedtodeterminewhetherafrequencydistribution
followsadefineddistribution.
A) goodnessoffit B) χ2C) F D) normality
21) Thedegreesoffreedomforaχ2goodnessoffittestwhenthereare6categoriesandasampleofsize1200is
A) 5 B) 6 C) 1199 D) 1205
12.2 TestsforIndependenceandtheHomogeneityofProportions
1 Performatestforindependence.
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
Provideanappropriateresponse.
1) Testthenullhypothesisofindependenceofthetwoclassifications,AandB,ofthe3×3contingencytable
shownbelow.Testusingα=0.10.
B
B1B2B3
A119 40 60
AA
255 23 22
A331 42 47
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MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
2) Thecontingencytablebelowshowstheresultsofarandomsampleof200registeredvotersthatwasconducted
toseewhethertheiropinionsonabillarerelatedtotheirpartyaffiliation.Useα
=0.05.
Party Opinion
Republican
Democrat
Independent
Approve Disapprove NoOpinion
42 20 14
50 24 18
10 16 6
Findthecriticalvalueχ 2
0,totesttheclaimofindependence.
A) 9.488 B) 7.779 C) 11.143 D) 13.277
3) Thecontingencytablebelowshowstheresultsofarandomsampleof200registeredvotersthatwasconducted
toseewhethertheiropinionsonabillarerelatedtotheirpartyaffiliation.
Party Opinion
Republican
Democrat
Independent
Approve Disapprove NoOpinion
42 20 14
50 24 18
10 16 6
Findthechisquareteststatistic,χ2,totesttheclaimofindependence.
A) 8.030 B) 11.765 C) 7.662 D) 9.483
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
4) Thecontingencytablebelowshowstheresultsofarandomsampleof200registeredvotersthatwasconducted
toseewhethertheiropinionsonabillarerelatedtotheirpartyaffiliation.
Party Opinion
Republican
Democrat
Independent
Approve Disapprove NoOpinion
42 20 14
50 24 18
10 16 6
Testtheclaimofindependence.
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
5) Aresearcherwantstodetermineifthenumberofminutesspentwatchingtelevisionperdayisindependentof
gender.Arandomsampleof315adultswasselectedandtheresultsareshownbelow.Findthecriticalvalue
χ2
0todetermineifthereisenoughevidencetoconcludethatthenumberofminutesspentwatchingtelevision
perdayisrelatedtogender.Useα=0.05.
Gender MinutesspentwatchingTVperday
Male
Female
030 3060 6090 90over
25 35 75 45
30 45 45 15
A) 7.815 B) 9.348 C) 11.345 D) 6.251
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6) Aresearcherwantstodetermineifthenumberofminutesspentwatchingtelevisionperdayisindependentof
gender.Arandomsampleof315adultswasselectedandtheresultsareshownbelow.Calculatethechi square
statisticχ2todetermineifthereisenoughevidencetoconcludethatthenumberofminutesspentwatching
televisionperdayisrelatedtogender.Useα=0.05.
Gender MinutesspentwatchingTVperday
Male
Female
030 3060 6090 90over
25 35 75 45
30 45 45 15
A) 18.146 B) 19.874 C) 20.912 D) 21.231
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
7) Aresearcherwantstodetermineifthenumberofminutesspentwatchingtelevisionperdayisindependentof
gender.Arandomsampleof315adultswasselectedandtheresultsareshownbelow.Isthereenough
evidencetoconcludethatthenumberofminutesspentwatchingtelevisionperdayisrelatedtogender?Useα
=0.05.
Gender MinutesspentwatchingTVperday
Male
Female
030 3060 6090 90over
25 35 75 45
30 45 45 15
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
8) Amedicalresearcherisinterestedindeterminingifthereisarelationshipbetweenadultsover50whoexercise
regularlyandlow,moderate,andhighbloodpressure.Arandomsampleof236adultsover50isselectedand
theresultsaregivenbelow.Findthecriticalvalueχ2
0totesttheclaimthatregularexerciseandlow,moderate,
andhighbloodpressureareindependent.Useα=0.01.
BloodPressure Low Moderate High
Reg.Exercise 35 62 25
NoReg.Exercise 21 65 28
A) 9.210 B) 9.348 C) 6.251 D) 5.991
9) Amedicalresearcherisinterestedindeterminingifthereisarelationshipbetweenadultsover50whoexercise
regularlyandlow,moderate,andhighbloodpressure.Arandomsampleof236adultsover50isselectedand
theresultsaregivenbelow.Calculatethechisquareteststatisticχ2totesttheclaimthatregularexerciseand
low,moderate,andhighbloodpressureareindependent.Useα=0.01.
BloodPressure Low Moderate High
Reg.Exercise 35 62 25
NoReg.Exercise 21 65 28
A) 3.473 B) 16.183 C) 18.112 D) 6.003
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SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
10) Amedicalresearcherisinterestedindeterminingifthereisarelationshipbetweenadultsover50whoexercise
regularlyandlow,moderate,andhighbloodpressure.Arandomsampleof236adultsover50isselectedand
theresultsaregivenbelow.Testtheclaimthatregularexerciseandlow,moderate,andhighbloodpressureare
independent.Useα=0.01.
BloodPressure Low Moderate High
Reg.Exercise 35 62 25
NoReg.Exercise 21 65 28
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
11) Asportsstatisticianisinterestedindeterminingifthereisarelationshipbetweenthenumberofhometeam
andvisitingteamlossesanddifferentsports.Arandomsampleof526gamesisselectedandtheresultsare
givenbelow.Findthecriticalvalueχ 2
0totesttheclaimthatthenumberofhometeamandvisitingteamlosses
isindependentofthesport.Useα=0.01.
Football Basketball Soccer Baseball
Hometeamlosses 39 156 25 83
Visitingteamlosses 31 98 19 75
A) 11.345 B) 12.838 C) 7.815 D) 9.348
12) Asportsstatisticianisinterestedindeterminingifthereisarelationshipbetweenthenumberofhometeam
andvisitingteamlossesanddifferentsports.Arandomsampleof526gamesisselectedandtheresultsare
givenbelow.Calculatethechisquareteststatisticχ2totesttheclaimthatthenumberofhometeamand
visitingteamlossesisindependentofthesport.Useα=0.01.
Football Basketball Soccer Baseball
Hometeamlosses 39 156 25 83
Visitingteamlosses 31 98 19 75
A) 3.290 B) 2.919 C) 5.391 D) 4.192
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
13) Asportsstatisticianisinterestedindeterminingifthereisarelationshipbetweenthenumberofhometeam
andvisitingteamlossesanddifferentsports.Arandomsampleof526gamesisselectedandtheresultsare
givenbelow.Testtheclaimthatthenumberofhometeamandvisitingteamlossesisindependentofthesport.
Useα=0.01.
Football Basketball Soccer Baseball
Hometeamlosses 39 156 25 83
Visitingteamlosses 31 98 19 75
14) Thedatabelowshowtheageandfavoritetypeofreadingof779randomlyselectedpeople.Testtheclaimthat
ageandpreferredreadingtypeareindependent.Useα=0.05.
Age CurrentEvents Mystery ScienceFiction History
1521 21 45 90 33
2130 68 55 42 48
3040 65 47 31 57
4050 60 39 25 53
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MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
15) Inaχ2testofindependence,thenullhypothesisisthat
A) thereisnotanassociation.
B) thereisanassociation.
C) eachelementofeachsethasthesameprobabilityofoccurrence.
D) therandomvariablesaredependent.
2 Performatestforhomogeneityofproportions.
SHORTANSWER.Writethewordorphrasethatbestcompleteseachstatementoranswersthequestion.
Provideanappropriateresponse.
1) Arandomsampleof400menand400womenwasrandomlyselectedandaskedwhethertheyplannedto
attendaconcertinthenextmonth.Theresultsarelistedbelow.Performahomogeneityofproportionstestto
testtheclaimthattheproportionofmenwhoplantoattendaconcertinthenextmonthisthesameasthe
proportionofwomenwhoplantoattendaconcertinthenextmonth.Useα
=0.05.
Men Women
Plantoattendconcert 230 255
Donʹtplantoattendconcert 170 145
2) Arandomsampleof100employeesfrom5differentcompanieswasrandomlyselected,andthenumberwho
takepublictransportationtoworkwasrecorded.Theresultsarelistedbelow.Performahomogeneityof
proportionstesttotesttheclaimthattheproportionwhotakepublictransportationtoworkisthesameinall5
companies.Useα=0.01.
Companies
12345
UsePublicTrans. 18 25 12 33 22
DonʹtUsePublicTrans. 82 75 88 67 78
MULTIPLECHOICE.Choosetheonealternativethatbestcompletesthestatementoranswersthequestion.
3) Inachisquaretestofhomogeneityofproportionswetesttheclaimsthat
A) differentpopulationshavethesameproportionsofindividualswiththesamecharacteristics.
B) acrossasinglesampletheproportionofindividualswiththesamecharacteristicisthesameasthe
population.
C) theproportionofindividualswithagivencharacteristicdoesnʹtchangeovertime.
D) theproportionofapopulationhavingagivencharacteristicisbasedonthehomogeneityofthe
population.
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Ch.12 InferenceonCategoricalData
AnswerKey
12.1 Goodnesso
f
FitTest
1 Performagoodnessoffittest.
12.2 TestsforIndependenceandtheHomogeneityofProportions
1 Performatestforindependence.
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2 Performatestforhomogeneityofproportions.
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