資源描述：
《商務(wù)統(tǒng)計(jì)相關(guān)知識(shí)(英文版).ppt》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在工程資料-天天文庫。
1、本資料來源Chapter8 IntervalEstimationPopulationMean:sKnownPopulationMean:sUnknownDeterminingtheSampleSizePopulationProportionApointestimatorcannotbeexpectedtoprovidetheexactvalueofthepopulationparameter.Anintervalestimatecanbecomputedbyaddingandsubtractingamarginoferro
2、rtothepointestimate.PointEstimate+/-MarginofErrorThepurposeofanintervalestimateistoprovideinformationabouthowclosethepointestimateistothevalueoftheparameter.MarginofErrorandtheIntervalEstimateThegeneralformofanintervalestimateofapopulationmeanisMarginofErrorandthe
3、IntervalEstimatetofindouttwopositivenumbersδandα,thelatterlyingbetween0and1,suchthattheprobabilitythattherandomIntervalcontainsthetrueparameteris1-αTherandomintervalisConfidenceintervalSuchaninterval,ifitexists,isknownasaconfidenceinterval;1?αisknownastheconfidenc
4、ecoefficient;andα(0<α<1)isknownasthelevelofsignificance.TheendpointsoftheconfidenceintervalareknownastheconfidencelimitsLowerconfidencelimitsandUpperconfidencelimitsIntervalEstimationofaPopulationMean:sKnownInordertodevelopanintervalestimateofapopulationmean,thema
5、rginoferrormustbecomputedusingeither:thepopulationstandarddeviations,orthesamplestandarddeviationssisrarelyknownexactly,butoftenagoodestimatecanbeobtainedbasedonhistoricaldataorotherinformation.Werefertosuchcasesasthesknowncase.IntervalEstimateofmIntervalEstimateo
6、faPopulationMean:sKnownwhere:isthesamplemean1-?istheconfidencecoefficientz?/2isthezvalueprovidinganareaof?/2intheuppertailofthestandardnormalprobabilitydistributionsisthepopulationstandarddeviationnisthesamplesize(7.1)Itisveryimportanttoknowthefollowingaspectsofin
7、tervalestimation:Equation(7.1)doesnotsaythattheprobabilityoftruemlyingbetweenthegivenlimitsis1?α.Sincem,althoughanunknown,isassumedtobesomefixednumber,eitheritliesintheintervaloritdoesnot.What(7.1)statesisthat,forthemethoddescribedinthischapter,theprobabilityofcon
8、structinganintervalthatcontainsmis1?α.ConfidencetothemethoditselfnottheintervalItisveryimportanttoknowthefollowingaspectsofintervalestimation:Theinterva
