《数据仓库与数据挖掘》第9章.ppt

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1、第7章:分类和预测Whatisclassification?Whatisprediction?IssuesregardingclassificationandpredictionClassificationbydecisiontreeinductionBayesianClassificationClassificationbyNeuralNetworksClassificationbySupportVectorMachines(SVM)Classificationbasedonconceptsfromassociationr

2、uleminingOtherClassificationMethodsPredictionClassificationaccuracySummary2021/7/211DataMining:ConceptsandTechniquesClassification:predictscategoricalclasslabels(discreteornominal)classifiesdata(constructsamodel)basedonthetrainingsetandthevalues(classlabels)inaclas

3、sifyingattributeandusesitinclassifyingnewdataPrediction:modelscontinuous-valuedfunctions,i.e.,predictsunknownormissingvaluesTypicalApplicationscreditapprovaltargetmarketingmedicaldiagnosistreatmenteffectivenessanalysisClassificationvs.Prediction2021/7/212DataMining

4、:ConceptsandTechniquesClassification—ATwo-StepProcessModelconstruction:describingasetofpredeterminedclassesEachtuple/sampleisassumedtobelongtoapredefinedclass,asdeterminedbytheclasslabelattributeThesetoftuplesusedformodelconstructionistrainingsetThemodelisrepresent

5、edasclassificationrules,decisiontrees,ormathematicalformulaeModelusage:forclassifyingfutureorunknownobjectsEstimateaccuracyofthemodelTheknownlabeloftestsampleiscomparedwiththeclassifiedresultfromthemodelAccuracyrateisthepercentageoftestsetsamplesthatarecorrectlycla

6、ssifiedbythemodelTestsetisindependentoftrainingset,otherwiseover-fittingwilloccurIftheaccuracyisacceptable,usethemodeltoclassifydatatupleswhoseclasslabelsarenotknown2021/7/213DataMining:ConceptsandTechniquesClassificationProcess(1):ModelConstructionTrainingDataClas

7、sificationAlgorithmsIFrank=‘professor’ORyears>6THENtenured=‘yes’Classifier(Model)2021/7/214DataMining:ConceptsandTechniquesClassificationProcess(2):UsetheModelinPredictionClassifierTestingDataUnseenData(Jeff,Professor,4)Tenured?2021/7/215DataMining:ConceptsandTechn

8、iquesSupervisedvs.UnsupervisedLearningSupervisedlearning(classification)Supervision:Thetrainingdata(observations,measurements,etc.)areaccompanied