STAT - CHAPTER 9 EXAM QUESTIONS WITH CORRECT ANSWERS GRADED A+ FOR

STAT - CHAPTER 9 EXAM QUESTIONS
WITH CORRECT ANSWERS GRADED
A+ FOR 2026-2027 ASSURED EXCEL!!
Ae________e________eisetheevalueeofeaestatisticethateestimatesetheevalueeofeaeparameter.e-
eeCORRECTeANSWERS-pointeestimate




Filleinetheeblankseinetheestatementebelow.

Thee_______erepresentsetheeexpectedeproportioneofeintervalsethatewillecontainetheeparametereifeae
largeenumbereofedifferentesampleseofesizeeneiseobtained.eIteisedenotede_______.e-
eeCORRECTeANSWERS-leveleofeconfidence;e(1-a)exe100%




Computeetheecriticalevalueezα/2

thatecorrespondsetoeae80%

leveleofeconfidence.e-eeCORRECTeANSWERS-za/2=1.28



Determineetheepointeestimateeofetheepopulationeproportion,etheemargineofeerroreforetheefollowing
econfidenceeinterval,eandetheenumbereofeindividualseinetheesampleewithetheespecifiedecharacteristi


c,ex,eforetheesampleesizeeprovided.

Lowerebound=0.123,eupperebound=0.407,en=1200e-eeCORRECTeANSWERS-
(a)eTheepointeestimateeofetheepopulationeproportioneise0.265.eFoundebyedoingep=u+b/2e=e0.123+0.
407/2e=e0.265

(b)eTheemargineofeerroreise0.142.eFoundebyedoingeu-b/2e=e0.407-0.123/2e=e0.142

(c)eTheenumbereofeindividualseinetheesampleewithetheespecifiedecharacteristiceise318.eFoundebyedoi
nge1200(0.265)e=e318



Ineaetrialeofe200epatientsewhoereceivede10-
mgedoseseofeaedrugedaily,e36ereportedeheadacheeaseaesideeeffect.eUseethiseinformationetoecomplete
epartse(a)ethroughe(d)ebelow.

, (a)eObtaineaepointeestimateeforetheepopulationeproportioneofepatientsewhoereceivede10-
mgedoseseofeaedrugedailyeandereportedeheadacheeaseaesideeeffect.e

(b)eVerifyethatetheerequirementseforeconstructingeaeconfidenceeintervaleaboutepeareesatisfied.eAreet
heerequirementseforeconstructingeaeconfidenceesatisfied?

(c)eConstructeae95%

confidenceeintervaleforetheepopulationeproportioneofepatientsewhoereceiveetheedrugeandereportehe
adacheeaseaesideeeffect.

(d)eInterpretetheeconfidenceeinterval.eWhichestatementebelowebesteinterpretsetheeinterval?e-
eeCORRECTeANSWERS-(a)epe=e0.18;efoundebyedoinge36/200e=e0.18



(b)eYes,etheerequirementseforeconstructingeaeconfidenceeintervaleareesatisfied.

(c)eThee95%econfidenceeintervaleise(0.127,0.233);efoundeviaeusingetheeproportionestatseoneStatCrun
ch

(d)eWeearee95%econfidentethatetheeintervalecontainsetheetrueevalueeofep.



Ineaepoll,e408eofe1020erandomlyeselectedeadultseagede18eoreolderestatedethatetheyebelieveethereeise
tooelittleespendingeonenationaledefense.eUseethiseinformationetoecompleteepartse(a)ethroughe(e)ebe
low.

(a)eObtaineaepointeestimateeforetheeproportioneofeadultseagede18eoreolderewhoefeelethereeisetooelittl
eespendingeonenationaledefense.

(b)eVerifyethatetheerequirementseforeconstructingeaeconfidenceeintervaleaboutepeareesatisfied.eAreet
heerequirementseforeconstructingeaeconfidenceesatisfied?

(c)eConstructeae99%econfidenceeintervaleforetheeproportioneofeadultseagede18eoreolderewhoebelieve
ethereeisetooelittleespendingeonenationaledefense.



(d)eIseitepossibleethatemoreethane45%eofeadultseagede18eoreolderebelieveethereeisetooelittleespending
eonenationaledefense?eIseitelikely?



(e)eUseetheeresultseofeparte(c)etoeconstructeae90%econfidenceeintervaleforetheepopulationeproportio
neofeadultseagede18eoreolderewhoedoenotebeliee-eeCORRECTeANSWERS-
(a)epe=e0.4;efoundebyedoinge408/1020e=e0.4

(b)eYes,etheerequirementseforeconstructingeaeconfidenceeintervaleareesatisfied.