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1、MedicalStatisticsMedicalStatistics(fullEnglish(fullEnglishclass)class)Ji-QianFangSchoolofPublicHealthSunYat-SenUniversityChapter2Chapter2ProbabilityandDistributionProbabilityandDistributionVocabularyforChapter2flippingadie擲骰子colorblindness色盲probability概率Conditionalprobability
2、條件概率Complementaryevent對立事件Odds優(yōu)勢Oddsratio優(yōu)勢比Bayes’formulaBayes’公式NormalDistribution正態(tài)分布standardnormaldistribution標準正態(tài)分布peak峰curve曲線area面積one-side單側(cè)VocabularyforChapter2percentile百分位數(shù)ReferenceRange參考值范圍BinomialDistribution二項分布PoissonDistributionPoisson分布independent獨立repeat重復Ad
3、ditiveproperty可加性Criticalvalue臨界值approximate近似Normalapproximation正態(tài)近似2.1ExplanationofProbability2.1ExplanationofProbabilityandRelatedConceptsandRelatedConcepts2.1.1ProbabilityòFlippingadie(骰子)Possibleoutcome:1,2,…,6Probabilityof“1”=1/6òColorblindnesstestPossibleoutcome:normal
4、,abnormalProbabilitiesof“abnormal”=?----Unknown!Survey:Randomlyselectednstudents,ifmofthemarecolorblinders,thenmprobabilityofabnormal≈nIngeneral,òEvents:thepossibleoutcomes,…E,E12òProbabilityoftheeventE:P(E).----between0and1Conditionalprobability:Undertheconditionthatappears,
5、theE1probabilityoftheevent=E2P(E2E1)ExampleNasopharyngealcarcinoma(鼻咽癌）andEBviruspositive(EB病毒陽性)P(nasopharyngealcarcinoma∣EBviruspositive)>P(nasopharyngealcarcinoma∣EBvirusnegative)2.1.2OddsòComplementaryevent:Ifthereareonlytwopossibleeventsandtheyareexclusive,denotedwithand
6、,thenEEP(E)=1?P()EEOddsofeventE:P(E)P(E)Odds==P(E)1?P(E)Question:FootballgamebetweenteamsAandB,IfP(Awin)=0.8,thenP(Bwin)=?Odds(Awin)=?Odds(Bwin)=?Eg.IftheincidenceratesofinfluenzainclassesA,BandCare60%,50%and40%thenP(A)0.60P(B)0.50OddsA===1.50OddsB===1.00P(A)0.40P(B)0.50P(C)0
7、.40Odds===0.67CP(C)0.60Odds:TomeasuringriskOddsratio:TocomparerisksOdds1.50AOddsratiobetweenAandC===2.24Odds0.67COdds1.00BOddsratiobetweenBandC===1.50Odds0.67C2.1.32.1.3BayesBayes’’formulaformulaTostudytherelationshipbetweenSmoking(A)andLungcancer(B)Isitinfeasible?1)Randomlyd
8、ividethesubjectsintotwogroups;2)Inviteonegrouptosmokeandforbidanothe
