STATS 240 EXAM 2 QUESTIONS WITH CORRECT ANSWERS

STATS 240 EXAM 2 QUESTIONS WITH
CORRECT ANSWERS

MarginalsProbabilitys-
sthesprobabilitysofsassingleseventswithoutsconsiderationsofsanysothersevent.sAlsoscalledssim

plesprobability.

ConditionalsProbabilitys-
sthesprobabilitysthatsanseventswillsoccursgivensthatsanotherseventshassalreadysoccurred



MutuallysExclusivesEventss-seventssthatscannotsoccurstogether

IndependentsEventss-
sTwoseventssaressaidstosbesindependent sifsthesoccurrencesofsonesdoessnotsaffectsthesprob

abilitysofsthesoccurrencesofsthesother;sP(A)=sPs(As|sF)

DependentsEventss-
sthesoccurrencesofsoneseventsaffectssthesprobabilitysofsthesoccurrencesofsthesothers;sP(As|

sB)sdoessnotsequalsPs(A)



ImportantsObservationss-sTwoseventssareseithersmutuallysexclusivesorsindependent.
mutuallysexclusiveseventssaresalwayssdependent.
Independentseventssaresneversmutuallysexclusive
2.sDependentseventssmaysorsmaysnotsbesmutuallysexclusive

ComplementarysEventss-
sThescomplementsofseventsA,sdenotedsbysAsbar,sisstheseventsthatsincludessallsthesoutcome

ssforsansexperimentsthatsaresnotsinsA
sP(A)s+sP(A-)s=1



IntersectionsofsEventss-
sthescollectionsofsallsoutcomessthatsarescommonstosbothsAsandsB;swrittensassAsnsBsorsAB



JointsProbabilitys-sthesprobabilitysofsthesintersectionsofstwosevents;swrittensassPs(AsandsB)

MultiplicationsRulestosfindsjointsprobabilitys-sPs(AsandsB)s=sPs(A)sPs(Bs|sA)=sPs(B)sPs(As|sB)