explainingη2单因素方差分析ppt课件.ppt

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1、ByHuiBianOfficeforFacultyExcellenceSPSSSeries1:ANOVAandFactorialANOVA1One-wayANOVAwithSPSSTwo-wayFactorialANOVAwithSPSSHowtointerpretSPSSoutputsHowtoreportresultsListoftopics2Weuse2009YouthRiskBehaviorSurveillanceSystem(YRBSS,CDC)asanexample.YRBSSmonit

2、orspriorityhealth-riskbehaviorsandtheprevalenceofobesityandasthmaamongyouthandyoungadults.ThetargetpopulationishighschoolstudentsMultiplehealthbehaviorsincludedrinking,smoking,exercise,eatinghabits,etc.Datausedinthisworkshop3ANOVAmeansAnalysisofVarianc

3、eANOVA:comparemeansoftwoormorelevelsoftheindependentvariableOneindependentvariableOnedependentvariableThebasictestusesFdistributionComparingmeansisaspecialcaseofaregressionanalysisOne-wayANOVA4ThepartitioningofthetotalsumofsquaresofdeviationsReasoningo

4、fANOVATotalsumofSquaresofdeviationsofDVIndependentvariable1Independentvariable2Independentvariable3Error5ResearchdesignBetween-subjectsdesign*:differentindividualsareassignedtodifferentgroups(levelofindependentvariable).Within-subjectsdesign:allthepart

5、icipantsareexposedtoseveralconditions.*Thispresentationonlyfocusesonbetween-subjectdesign.One-wayANOVA6DataconsiderationsIndependentvariable(factorvariable)iscategorical.Dependentvariableshouldbequantitative(intervallevelofmeasurement).AssumptionsIndep

6、endent:eachgroupisanindependentrandomsamplefromanormalpopulation.Normality:analysisofvarianceisrobusttodeparturesfromnormality,althoughthedatashouldbesymmetric.Homogeneity:thegroupsshouldcomefrompopulationswithequalvariances.One-wayANOVA7Example:Resear

7、chdesign:between-subjectsdesignResearchquestion:Isthereadifferenceinsedentarybehavioracrossfourgradelevels?Oneindependentvariable:Gradewith4levels:9th,10th,11th,and12thgrade(Q3r).Onedependentvariable:sedentarybehavior(Q81:HowmanyhourswatchTV)Higherscor

8、eofQ81=MorehoursonwatchingTV.One-wayANOVA8Runningaone-waybetween-subjectsANOVAwithSPSS.SelectAnalyzeGeneralLinearModelUnivariateMoveQ81MoveQ3rClickPostHocOne-wayANOVA9One-wayANOVAPostHocComparisonsThisanalysesassessmeandifferencesbetwee