当代市场调研10E全套配套课件中英文PPTch13.ppt 23页

ChapterThirteen13-1 Theentiregroupofpeopleaboutwhominformationisneeded;alsocalledtheuniverseorpopulationofinterest.Theprocessofobtaininginformationfromasubsetofalargergroup.SamplingPopulationTheConceptofSampling13-2KeyTerms&Definitions Census:Datacollectionfromorabouteverymemberofthepopulationofinterest.Alsocalledcanvassingthepopulationbyaskingeveryoneasetofquestions.Sample:Asubsetofallthemembersofapopulationofinterest.Hopefullythatsubsetisstatisticallyrepresentativeofthegeneralpopulation.Censusvs.Sample13-3KeyTerms&Definitions DevelopingaSamplingPlan13-4KeyTerms&Definitions 1.DefinetheTargetPopulationDeterminethecharacteristicsofthoseyouareinterestedinstudying.Determinewhichgroupofpeopleorentitiesaboutwhichyouwanttolearnmore.2.ChoosetheDataCollectionMethodDeterminehowyoucollectthesample-suchasmail,Internet,telephone,mallintercept,etc.3.SelecttheSampleFrameAlistofpopulationelementsfromwhichunitstobesampledcanbeselected.DevelopingaSamplingPlan13-5KeyTerms&Definitions 4.SelecttheSamplingMethodDeterminehowyouwillgetthesamplelistthroughprobabilityornon-probabilitymethods.5.DeterminetheSampleSizeWhatisthelevelofaccuracyyouwanttoachieve;thetimeandmoneyyouhavetodothesurvey,andthedatacollectionmethod?6.DetermineOperationalProceduresThisistheplanofhowtogoaboutactuallychoosingandinterviewingtherespondents.7.ExecutetheSamplingPlanFieldworkersmustbetrainedtoexecutethesamplingplanproperly.DevelopingaSamplingPlan13-6KeyTerms&Definitions 1.DefiningthePopulationofInterest13-7KeyTerms&Definitions 2.ChooseaDataCollectionMethod13-8KeyTerms&DefinitionsThemainmethodsare:Personal,suchasmallintercepts,etc.TelephoneMailorotherself-administeredInternet,blendedsamplesThiswasdiscussedinthechapteronquestionnairedesign,also.Thesampleplanwilldependonthedatacollectionmethod,too. 3.IdentifytheSamplingFrame13-9KeyTerms&DefinitionsThisisalistofthemembersorelementsofthepopulationfromwhichunitstobesampledaretobeselected.Thereisseldomaperfectcorrespondencebetweenthesampleframeandthepopulationofinterest.Explainhowacity’stelephonebookcouldbeusedasasampleframeofpeopleinthecitywithtelephones.Whataretheadvantagesanddisadvantagesofusingthatframe? 4.SamplingMethods13-10KeyTerms&Definitions Asampleselectedbyassigninganumbertoeveryelementofthepopulationandthenusingsomemethodforrandomlyselectingelementstobeinthesamplesuchasrandomdigitdialing.Asampleinwhichtheentirepopulationisnumberedandelementsareselectedusingaskipinterval–every“nth”nameisselected.SimpleRandomSystematicProbabilitySampling13-11KeyTerms&Definitions Asamplethatisforcedtobemorerepresentativethroughsimplerandomsamplingofmutuallyexclusiveandexhaustivesubsetseitherproportionallyordisproportionally.Goodfordatathatarenotnormallydistributed.Asampleinwhichthesamplingunitsareselectedfromanumberofsmallgeographicareastoreducedatacollectioncosts.ClusterStratifiedProbabilitySampling13-12KeyTerms&Definitions StratifiedSamplingAllocationsProportionalAllocation:Samplinginwhichthenumberofelementsselectedfromastratumisdirectlyproportionaltothesizeofthestratumrelativetothesizeofthepopulation.Disproportional,orOptimal,Allocation:Samplinginwhichthenumberofelementstakenfromagivenstratumisproportionaltotherelativesizeofthestratumandthestandarddeviationofthecharacteristicunderconsideration.13-13KeyTerms&Definitions MultistageSamplingGeographicareasselectedfornationalorregionalsurveysinprogressivelysmallerpopulationunits,suchascounties,thenresidentialblocks,thenhomes.13-14KeyTerms&Definitions SamplingandNonsamplingErrorPopulationParameterAvaluethataccuratelyportraysortypifiesafactorofacompletepopulation,suchasaverageageorincome.13-15KeyTerms&Definitions Errorthatoccursbecausethesampleselectedisnotperfectlyrepresentativeofthepopulation.Allerrorotherthansamplingerror-alsocalled“measurementerror.”SamplingErrorNonsamplingErrorSamplingandNonsamplingError13-16KeyTerms&Definitions Asamplebasedonusingpeoplewhoareeasilyaccessible–suchasmallinterceptsorotherhightrafficlocations.Asampleinwhichtheselectioncriteriaarebasedontheresearcher’spersonaljudgmentabouttherepresentativenessofthepopulationunderstudy.Theresearcherselectswhoshouldbeinthestudy.JudgmentConvenienceNonprobabilitySampling13-17KeyTerms&Definitions Asampleinwhichquotas,basedondemographicorclassificationfactorsselectedbytheresearcher,areestablishedforpopulationsubgroups.Asampleinwhichadditionalrespondentsareselectedbasedonreferralsfrominitialrespondents.SnowballQuotaNonprobabilitySampling13-18KeyTerms&Definitions DeterminetheSampleSizeDeterminingthesamplesizewillbebasedonfactorssuchasthelevelofaccuracyyouwanttoachieve,thetimeandmoneyyouhavetodothesurvey,andonthesamplingcollectionmethod.Theactualsizecouldbedeterminedbyaformulaorbysomeruleofthumbbasedonexperience.5.DeterminetheSampleSize13-19KeyTerms&Definitions 6.DevelopOperationalProcedures13-20KeyTerms&DefinitionsSelectSampleUnitsYouroperationalplantoconducttheprobabilityornon-probabilitysampling.Determinethephasesofthesampleselectionprocess.Multi-stagesamplinginvolvescombiningsamplingmethods.Forprobabilitysampling,theseinstructionsneedtobedetailed,clear,andunambiguousandshouldeliminateanyinterviewerdiscretionregardingtheselectionofspecificsampleelements. ConductFieldworkTheexecutionphaseoftheresearch.Administeringthequestionnaire-sendingthemailers,makingthephonecalls,conductingthemallintercepts,etc.Asmentionedinthelastslide,ifaprobabilitysampleisused,theinstructionsneedtobefollowedtotheletter.Goodtrainingandsupervisionoffieldworkpersonnel(iftheyareused)isofutmostimportance.7.ExecutethePlan13-21KeyTerms&Definitions Targetrespondentscancompletethesurveyattheirconvenience.Datacollectionisinexpensive.Surveysoftwarecanfacilitatethedatacollectionprocess.Thesurveycanbecompletedquickly.Samplemightnotberepresentativeofthepopulation.Youcannotalwaysbesurewhoiscompletingthesurvey.Maintainingrespondentconfidentiallycanbeachallenge.Datasecurityissuescanbedifficulttomanage.InternetSamplingProsCons13-22KeyTerms&Definitions 13-23KeyTerms&DefinitionsSamplingPopulationCensusSampleDevelopingaSamplePlanSamplingFrameBlendedSamplesRandomDigitDialProbabilitySamplesNonprobabilitySamplesSampleSizePopulationParameterSamplingErrorLinksandbuttonareactivewhenin“SlideShowMode”KeyTerms&DefinitionsNonsamplingErrorSimpleRandomSampleSystematicSamplingStratifiedSampleProportionalAllocationDisproportional,orOptimal,AllocationClusterSampleMultistageAreaSamplingConvenienceSamplesJudgmentSamplesQuotaSamplesSnowballSamples