医学统计学ppt英文课件CH01introdu

PostgraduatebooksrecommendedbyDegreeManagementandPostgraduateEducationBureau,MinistryofEducationMedicalStatistics(the2ndedition),Arrangement:total72classhours,twoclasseseachweek,chapter1IntroductionKeydefinitionsthestepsformedicalstatisticsBriefhistoryofStatistics,StatisticsThesciencefordatacollection,sorting,andanalysis.,Definition：thesciencethatstudythecollection,sortingandanalysisofmedicaldata.Characteristics：1、Usingthequantitytoreflectthequality2、Usingchanceevents(uncertainty)toreflecttheinevitability(rules),MedicalStatistics,Learningobjectives：1、BasicprinciplesandmethodsofStatistics（LearningEmphasis）2、ApplicationStatistics(ClinicalMedicine,PreventiveMedicine,andHealthCareManagement),MedicalStatistics,Purpose：atoolformedicalresearchEmphasis:statisticalindicatorsusedforcalculatingorcomparingthequantitativecharacteristicsofpopulationExample:healthexpectationinfantmortality,MedicalStatistics,Section1.Keydefinitions,variable,individual,sampleandpopulation,individual（observatoryunit）：thebasicunitinstatisticalresearch,itdependsonthepurpose.variable（indicator）：individualcharacteristicsexamples:height、weight、gender、bloodtype、treatmenteffectetc.,Variablevalue：thevalueofvariablesExamples:height1.65metersweight52kggenderfemalebloodtype“O”laboratorytestnegativetreatmenteffectbetterData:composedofalotofvariablevalues.Example:Dataforbloodglucose,homogeneity：commoncharacteristicsforthegivenindividualsexample：theheightsoftheboyswiththeageof7livinginChangsha2004variation:differenceexistingamongthevariablevaluesofhomogeneityindividualsexample:thedifferentheightsoftheboyswiththeageof7livinginChangsha2004,Definition：thewholehomogeneityindividualsdeterminedbyspecificpurpose.example：alltheheightsofboysat7thatlivedinChangsha2004finitepopulation：thespace,timeandpopulationforaspecificpopulationhavebeenlimited.infinitepopulation：notimeandspacelimitsforthepopulation.Suchpopulationsonlyexistinimagination,soitiscalledinfinitepopulation.,population,definition：thesetofvariablevaluesofsomeindividualssampledfromthepopulationatrandom.Example:theheightsof200boysat7fromChangsha.,sample,Samplingstudy,Sampleinformation(statistic),Populationcharacteristics（parameter）,inference,note：samplingisonlythewaytogetinformation,inferringthepopulationisourpurpose,、variableanddata,measurementdata:itisalsocalledasquantitativeornumericaldata.Itsvalueisquantitative.Measurementdataalwayshasmeasurementunits.example：heightdata,weightdata,enumerationdata:qualitativeorcountdata.Forsuchdata,itneedstoclassifytheobservationunitsbeforeandcountthem.Itsvalueappeardifferentcharacteristicsandsorts.,Binomial:gender,liveordeath,yesorno.Multiple：bloodtype,A、B、O、AB.,rankeddata:ordinalorsemi-quantitativedata.Itneedtoclassifyobservatoryunitsintodifferentclassesaccordingtheextentbeforecalculatethefrequenciesofeachgroups.Thereexistsobviousdifferencesamongdifferentclasses.example:toevaluatethetreatmenteffectofonedrugonheartfailure,weusetheindicator(cured,better,worsen,dead)toassessthetreatmenteffect.Choosingofstatisticalmethodsdependsonthedatatypetoagreatextent。,Datatransformation,example：WBC（1/m3）countoffivepersons：300060005000800012000quantitativevariablelowernormalnormalnormalhigherqualitativevariableBinomialdata:normal3persons;abnormal2personsMultiplecategorydata:lower1person;normal;3persons;higher1person,error,definition：thedifferencebetweenmeasurementvalueandtruevalue.1、randerror：unstableandchangingatrandomerrorsthatcausedbyuncontrolledfactors.Commonly,randerrorsarereferredtothoseerrorsappearingduringrepeatedmeasurementsandsampling.Often,measurementerrorisextremelylowerthansamplingerror.InStatistics,samplingerroristhemainstudycontents.,2.Nonrandomerrorisdividedintosystematicerrorandnonsystematicerror:Systematicerror:itisproducedinexperimentandkeepsconstantorchangesaccordingcertainrules.Usually,itsreasonsareknownandcontrollable.Nonsystematicerror（grosserror）:itisalwayscausedbyobviousgrosses.,、frequencyandprobability,1FrequencyGiventhesamecondition,repeatatrialforntimesindependently.Amongntrials,Aappearsformtimes，sotheratioofm/niscalledthefrequencyofrandomeventAamongntrials.,2probability:thelikelihoodofrandomevents.Giventhesamecondition,repeatatrialforntimesindependently.Amongntrials,Aappearsfortimes，sotheratioofiscalledthefrequencyofrandomeventA.Asnincreasesgradually,thefrequencywillapproachaconstant.TheconstantiscalledtheprobabilityofrandomeventAandexpressedin.Incommon,itisabbreviatedas.,Range：,Frequencyisusedtodescribethesample,whiletheprobabilityforthepopulation.m/nistheestimationof.Astrialsincreases,theestimationvalueismorereliable.,smallprobabilityevent:Becausetheconclusionsaremadebasedonacertainsignificancelevel,statisticiansalwaysselectasjudgecriterion.Sosucheventswitharecalledsmallprobabilityevents.Itmeansthatsucheventshappenrarelyandcanberegardedasnonoccurrence.,Section2thestepsforstatisticalwork,Here,itmeansstatisticaldesign,themostimportantfactorforasuccessfulresearch.Itinvolvesthearrangementsfortheprocessofdatacollection,sortingandanalysis.,design,3control,Threeprinciplesforexperimentdesign,1randomization,2.Replication,objective：togatheraccurateandreliablerawdatadatasources：statisticalreportingroutinerecordspurposivesurveysorexperimentsstatisticalyearbookandspecialdatabookrequirements：1、randomization2、sufficientsamplesize,Datacollection,Datasorting,Itistheprocessthatcleansandsystematizesrawdata.Datasortingpreparestherequireddatafornextstep,dataanalysis.,Data/statisticalanalysis,objective：toillustratetheruleshiddeninthedata.Itincludestwoaspe