应用统计学_卡方检验.ppt

《应用统计学_卡方检验.ppt》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、BEO2255AppliedStatisticsforBusinessWeekSix–Analyzingcategoricaldata:Chi-squaredtestsThisweeklecturewillcover...Analysingcategoricaldata(nominal)Chi-squaretestofdifferencesbetweenproportionsChi-squaretestofindependenceSPSS单样本非参数检验总体分布的chi-square检验(1)目的:根据样本数据推断总体的分布与某个已知分布是否有

2、显著差异---吻合性检验。适用于分类资料的统计推断SPSS单样本非参数检验总体分布的chi-square检验(2)基本假设:H0:总体分布与理论分布无显著差异(3)基本方法根据已知总体的构成比计算出样本中各类别的期望频数，计算实际观察频数与期望频数的差距,即：计算卡方值卡方值较小,则实际频数和期望频数相差较小.如果P大于a,不能拒绝H0,认为总体分布与已知分布无显著差异.反之SPSS单样本卡方检验总体分布的chi-square检验(4)基本操作步骤:菜单:analyze->nonparametrictest->chisquare选定待检验变量入te

3、stvariablelist框确定待检验个案的取值范围(expectedrange)getfromdata:全部样本usespecifiedrange:用户自定义个案范围指定期望频数(expectedvalues)allcategoriesequal:所有类别有相同的构成比value:用户自定义构成比CategoricalvariableVariablesthatdescribecategoriesofentitiesDealingwiththemallthetimeinstatisticsMakingcomparisonsamongvariabl

4、esForexample,whetherconsumerspreferaparticularbrandofaproductamongothercompetingbrands.CheckingwhetherthereisarelationshipbetweentwocategoricalvariablesGenderandpreferenceforaproduct,whetherthepreferenceforaproductisindependentfromgenderChi-squaretestfordifferencesbetweenpropo

5、rtionsThistestinvolveswithnominaldataproducedbymultinomialexperimentItisageneralisationofabinomialexperimentThesetestthenullhypothesisthatdatainthetargetpopulationhasaparticularprobabilitydistribution.Example1Wemighttestwhetherconsumersareindifferenttowhichoffourmaterials(glas

6、s,plastic,steeloraluminium)thatcouldbeusedtomakesoftdrinkcontainers.Thenullhypothesisisthattheyareindifferent(orthatequalnumberspreferglass,plastic,steelandaluminium).Example1DataLetpGbetheprobabilitythatanindividualselectedatrandomwillnominateglassashis/herpreferenceifrequire

7、dtomakeachoice.SimilarlyforpP(plastic),pS(steel)andpA(aluminium)HypothesesHO:pG=pP=pS=pA=0.25.HA:atleastonepi0.25.Thealternativeisthatatleastonematerialismorepreferred(orlesspreferred)thantheothers.Example1cont..Procedure:Selectarandomsampleof,say,100consumersanddeterminethei

8、rpreferences.UnderthenullhypothesisWeexpect25consumerstonomin