File:dCh10,dChapterd10dTestdBank
True/False
1. Toddeterminedifdtheredisdaddifferencedindthedstrengthdofdsteeldproduceddfromdtwoddiffere
ntdproductiondprocesses,dadprocessdmanagerdwillddrawdindependentdsamplesdfromdthedtwo
dprocessesdanddcomparedtheddifferencedindthedsampledmeans.
Ans:dTrue
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dEasy
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
2. Theddifferencedindtwodsampledmeansdisdnormallyddistributeddfordsampledsizesd≥d30,donlydi
fdthedpopulationsdarednormallyddistributed.
Ans:dFalse
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dEasy
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
3. Ifdthedsampledsizesdaredgreaterdthand30danddthedpopulationdvariancesdaredknown,dthedbas
isdfordstatisticaldinferencesdaboutdtheddifferencedindtwodpopulationdmeansdusingdtwodindep
endentdrandomdsamplesdisdthedz-
statistic,dregardlessdofdthedshapesdofdthedpopulationddistributions.
Ans:dTrue
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dMed
ium
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
,4. Ifdthedsampledsizesdaredsmall,dbutdthedpopulationsdarednormallyddistributeddanddthedpop
ulationdvariancesdaredknown,dthedz-
statisticdcandbeduseddasdthedbasisdfordstatisticaldinferencesdaboutdtheddifferencedindtwodpop
ulationdmeansdusingdtwodindependentdrandomdsamples.
Ans:dTrue
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dMed
ium
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
5. Ifdad98%dconfidencedintervaldfordtheddifferencedindthedtwodpopulationdmeansddoesdnotdc
ontaindzero,dthendthednulldhypothesisdofdzeroddifferencedbetweendthedtwodpopulationdmea
nsdcannotdbedrejecteddatdad0.02dleveldofdsignificance.
Ans:dFalse
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dHard
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
6. Ifdad90%dconfidencedintervaldfordtheddifferencedindthedtwodpopulationdmeansdcontainsdz
ero,dthendthednulldhypothesisdofdzeroddifferencedbetweendthedtwodpopulationdmeansdcann
otdbedrejecteddatdad0.10dleveldofdsignificance.
Ans:dTrue
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dHard
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
7. Ifdthedpopulationsdarednormallyddistributeddbutdthedpopulationdvariancesdaredunknowndth
edz-
statisticdcandbeduseddasdthedbasisdfordstatisticaldinferencesdaboutdtheddifferencedindtwodpopula
tiondmeansdusingdtwodindependentdrandomdsamples.
Ans:dFalse
,Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
8. Ifdthedpopulationsdarednormallyddistributeddbutdthedpopulationdvariancesdaredunknowndth
edt-
statisticdcandbeduseddasdthedbasisdfordstatisticaldinferencesdaboutdtheddifferencedindtwodpopul
ationdmeansdusingdtwodindependentdrandomdsamples.
Ans:dTrue
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
9. Ifdthedvariancesdofdthedtwodpopulationsdarednotdequal,ditdisdappropriatedtodusedthed“pool
ed”dformuladtoddeterminedthedt-
statisticdfordthedhypothesisdtestdofdtheddifferencedindthedtwodpopulationdmeans.
Ans:dFalse
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
10. Ifdthedpopulationsdarednormallyddistributeddanddthedvariancesdofdthedtwodpopulationsdar
edequal,ditdisdappropriatedtodusedthed“pooled”dformuladtoddeterminedthedt-
statisticdfordthedhypothesisdtestdofdtheddifferencedindthedtwodpopulationdmeans.
Ans:dTrue
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
, LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
11. Ifdthedpopulationsdarednormallyddistributeddanddthedvariancesdofdthedtwodpopulationsda
rednotdequal,ditdisdappropriatedtodusedthed“unpooled”dformuladtoddeterminedthedt-
statisticdfordthedhypothesisdtestdofdtheddifferencedindthedtwodpopulationdmeans.
Ans:dTrue
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
12. Indorderdtodconstructdandintervaldestimatedfordtheddifferencedindthedmeansdofdtwodnorma
llyddistributeddpopulationsdwithdunknowndbutdequaldvariances,dusingdtwodindependentdsam
plesdofdsizedn1d anddn2,dwedmustdusedadtddistributiondwithd(n1d+dn2)ddegreesdofdfreedom.
Ans:dFalse
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
13. Indorderdtodconstructdandintervaldestimatedfordtheddifferencedindthedmeansdofdtwodno
rmallyddistributeddpopulationsdwithdunknowndbutdequaldvariances,dusingdtwodindepend
entdsamplesdofdsizedn1d anddn2,dwedmustdusedadtddistributiondwithd(n1d+dn2d −d2)ddegreesdof
dfreedom.
Ans:dTrue
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
True/False
1. Toddeterminedifdtheredisdaddifferencedindthedstrengthdofdsteeldproduceddfromdtwoddiffere
ntdproductiondprocesses,dadprocessdmanagerdwillddrawdindependentdsamplesdfromdthedtwo
dprocessesdanddcomparedtheddifferencedindthedsampledmeans.
Ans:dTrue
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dEasy
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
2. Theddifferencedindtwodsampledmeansdisdnormallyddistributeddfordsampledsizesd≥d30,donlydi
fdthedpopulationsdarednormallyddistributed.
Ans:dFalse
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dEasy
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
3. Ifdthedsampledsizesdaredgreaterdthand30danddthedpopulationdvariancesdaredknown,dthedbas
isdfordstatisticaldinferencesdaboutdtheddifferencedindtwodpopulationdmeansdusingdtwodindep
endentdrandomdsamplesdisdthedz-
statistic,dregardlessdofdthedshapesdofdthedpopulationddistributions.
Ans:dTrue
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dMed
ium
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
,4. Ifdthedsampledsizesdaredsmall,dbutdthedpopulationsdarednormallyddistributeddanddthedpop
ulationdvariancesdaredknown,dthedz-
statisticdcandbeduseddasdthedbasisdfordstatisticaldinferencesdaboutdtheddifferencedindtwodpop
ulationdmeansdusingdtwodindependentdrandomdsamples.
Ans:dTrue
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dMed
ium
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
5. Ifdad98%dconfidencedintervaldfordtheddifferencedindthedtwodpopulationdmeansddoesdnotdc
ontaindzero,dthendthednulldhypothesisdofdzeroddifferencedbetweendthedtwodpopulationdmea
nsdcannotdbedrejecteddatdad0.02dleveldofdsignificance.
Ans:dFalse
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dHard
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
6. Ifdad90%dconfidencedintervaldfordtheddifferencedindthedtwodpopulationdmeansdcontainsdz
ero,dthendthednulldhypothesisdofdzeroddifferencedbetweendthedtwodpopulationdmeansdcann
otdbedrejecteddatdad0.10dleveldofdsignificance.
Ans:dTrue
Response:dSeedsectiond10.1dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeansdusingdthedzdStatisticd(PopulationdVariancesdKnown)dDifficulty:dHard
LearningdObjective:d10.1:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddifferen
cedindtwodmeansdwithdknowndpopulationdvariancesdusingdthedzdstatistic.
7. Ifdthedpopulationsdarednormallyddistributeddbutdthedpopulationdvariancesdaredunknowndth
edz-
statisticdcandbeduseddasdthedbasisdfordstatisticaldinferencesdaboutdtheddifferencedindtwodpopula
tiondmeansdusingdtwodindependentdrandomdsamples.
Ans:dFalse
,Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
8. Ifdthedpopulationsdarednormallyddistributeddbutdthedpopulationdvariancesdaredunknowndth
edt-
statisticdcandbeduseddasdthedbasisdfordstatisticaldinferencesdaboutdtheddifferencedindtwodpopul
ationdmeansdusingdtwodindependentdrandomdsamples.
Ans:dTrue
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
9. Ifdthedvariancesdofdthedtwodpopulationsdarednotdequal,ditdisdappropriatedtodusedthed“pool
ed”dformuladtoddeterminedthedt-
statisticdfordthedhypothesisdtestdofdtheddifferencedindthedtwodpopulationdmeans.
Ans:dFalse
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
10. Ifdthedpopulationsdarednormallyddistributeddanddthedvariancesdofdthedtwodpopulationsdar
edequal,ditdisdappropriatedtodusedthed“pooled”dformuladtoddeterminedthedt-
statisticdfordthedhypothesisdtestdofdtheddifferencedindthedtwodpopulationdmeans.
Ans:dTrue
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
, LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
11. Ifdthedpopulationsdarednormallyddistributeddanddthedvariancesdofdthedtwodpopulationsda
rednotdequal,ditdisdappropriatedtodusedthed“unpooled”dformuladtoddeterminedthedt-
statisticdfordthedhypothesisdtestdofdtheddifferencedindthedtwodpopulationdmeans.
Ans:dTrue
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
12. Indorderdtodconstructdandintervaldestimatedfordtheddifferencedindthedmeansdofdtwodnorma
llyddistributeddpopulationsdwithdunknowndbutdequaldvariances,dusingdtwodindependentdsam
plesdofdsizedn1d anddn2,dwedmustdusedadtddistributiondwithd(n1d+dn2)ddegreesdofdfreedom.
Ans:dFalse
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
LearningdObjective:d10.2:dTestdhypothesesdandddevelopdconfidencedintervalsdaboutdtheddif
ferencedindtwodmeansdofdindependentdsamplesdwithdunknowndpopulationdvariancesdusingd
thedtdtest.
13. Indorderdtodconstructdandintervaldestimatedfordtheddifferencedindthedmeansdofdtwodno
rmallyddistributeddpopulationsdwithdunknowndbutdequaldvariances,dusingdtwodindepend
entdsamplesdofdsizedn1d anddn2,dwedmustdusedadtddistributiondwithd(n1d+dn2d −d2)ddegreesdof
dfreedom.
Ans:dTrue
Response:dSeedsectiond10.2dHypothesisdTestingdanddConfidencedIntervalsdaboutdthedDiffe
rencedindTwodMeans:dIndependentdSamplesdanddPopulationdVariancesdUnknowndDifficul
ty:dMedium
