第五章 数值变量资料的假设检验课件.ppt
第四章(二)假设检验
Hypothesistesting山东大学公共卫生学院刘静7第五章数值变量资料的假设检验2
2Example1ThedeanofamedicalschoolstatesthatthestudentsoftheschoolareahighlyintelligentgroupwithanaverageIQof135.Doyoubelievehim?Thestudentsofourschoolareveryclever.TheaverageIQofourstudentsisupto135.7第五章数值变量资料的假设检验2
3Suppose?isreally135RandomSamplesample?PopulationNotnecessarily.Samplingerrorwillalwayscausethesamplemeantodeviatefromthepopulationmean.7第五章数值变量资料的假设检验2
4H0:?=?0,then~N(?0,?2/n)Fig.1DistributionofsamplemeanswhenH0istrueTosuspectH0?07第五章数值变量资料的假设检验2
5H0:?=?0?0Fig.2:Regionsofrejectionandnonrejection
inhypothesistestingofonesamplemeanRejectregionNonrejectionregionareaofnonrejectionregion,1-?areaofrejectionregion,?Criticalvalueofsamplemean7第五章数值变量资料的假设检验2
6Fig.3:Criticalvalueoftinhypothesistesting
foronesamplemeanareaofnonrejectionregion,1-?areaofrejectionregion,?Criticalvalueoft:-t?,?tDegreesoffreedom,?=n-17第五章数值变量资料的假设检验2
7-tt07第五章数值变量资料的假设检验2
8Arandomsampleof10studentsisdrawn;theirIQsareasfollows:1151401331251201261361241321297第五章数值变量资料的假设检验2
9Calculatethevalueoftthatcorrespondstothemeanofthesample.7第五章数值变量资料的假设检验2
10-2.935-t?,?=-1.833Inthisexample,thetscore(-2.935)doesfallintheregionofrejection.Therefore,thenullhypothesisshouldberejected,andnaturallythealternativehypothesisisaccepted.Conclusion!!?=n-1=9t7第五章数值变量资料的假设检验2
11StepstotestahypothesisaboutameanStatethenullandalternativehypotheses,H0andH1.Selectthedecisioncriterion?(or“significancelevel”).Establishthecriticalvalue(s)ofthetestingstatistic.Drawarandomsamplefromthepopulation,thencalculatethemeanandthestandarddeviationofthatsampleandestimatesamplingerror().Calculatethevalueoftheteststatistictcorrespondingtothemeanoft