2019《计量经济学导论》ppt课件.ppt

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1、轨道交通企业日常运输组织的指挥中枢，担负着组织行车、提高运营服务质量、确保运输安全、完成乘客运输计划、实现列车运行图的重要责任MultipleRegressionAnalysis:FurtherIssuesChapter6Wooldridge:IntroductoryEconometrics:AModernApproach,5e©2013CengageLearning.AllRightsReserved.Maynotbescanned,copiedorduplicated,orpostedtoapubliclyacce

2、ssiblewebsite,inwholeorinpart.轨道交通企业日常运输组织的指挥中枢，担负着组织行车、提高运营服务质量、确保运输安全、完成乘客运输计划、实现列车运行图的重要责任MultipleRegressionAnalysis:FurtherIssuesMoreonFunctionalFormMoreonusinglogarithmicfunctionalformsConvenientpercentage/elasticityinterpretationSlopecoefficientsofloggedva

3、riablesareinvarianttorescalingsTakinglogsofteneliminates/mitigatesproblemswithoutliersTakinglogsoftenhelpstosecurenormalityandhomoscedasticityVariablesmeasuredinunitssuchasyearsshouldnotbeloggedVariablesmeasuredinpercentagepointsshouldalsonotbeloggedLogsmustnotb

4、eusedifvariablestakeonzeroornegativevaluesItishardtoreversethelog-operationwhenconstructingpredictions©2013CengageLearning.AllRightsReserved.Maynotbescanned,copiedorduplicated,orpostedtoapubliclyaccessiblewebsite,inwholeorinpart.轨道交通企业日常运输组织的指挥中枢，担负着组织行车、提高运营服务质

5、量、确保运输安全、完成乘客运输计划、实现列车运行图的重要责任MultipleRegressionAnalysis:FurtherIssuesUsingquadraticfunctionalformsConcaveexperienceprofileExample:WageequationThefirstyearofexperienceincreasesthewagebysome.30$,thesecondMarginaleffectofexperienceyearby.298-2(.0061)(1)=.29$etc.©2

6、013CengageLearning.AllRightsReserved.Maynotbescanned,copiedorduplicated,orpostedtoapubliclyaccessiblewebsite,inwholeorinpart.轨道交通企业日常运输组织的指挥中枢，担负着组织行车、提高运营服务质量、确保运输安全、完成乘客运输计划、实现列车运行图的重要责任MultipleRegressionAnalysis:FurtherIssuesWagemaximumwithrespecttoworkexperi

7、enceDoesthismeanthereturntoexperiencebecomesnegativeafter24.4years?Notnecessarily.Itdependsonhowmanyobservationsinthesamplelierightoftheturnaroundpoint.Inthegivenexample,theseareabout28%oftheobservations.Theremaybeaspeci-ficationproblem(e.g.omittedvariables).©20

8、13CengageLearning.AllRightsReserved.Maynotbescanned,copiedorduplicated,orpostedtoapubliclyaccessiblewebsite,inwholeorinpart.轨道交通企业日常运输组织的指挥中枢，担负着组织行车、提高运营服务质量、确保运输安全、