医学统计学ppt英文课件CH05descriptionofcategoricaldata

Chapter5Descriptionofcategoricaldata Content Rate proportionandratioApplicationofrelativenumbersStandardizationofrateDynamicseriesandanalysisindex Section1RelativeNumbers 1 Rate2 Proportion3 Ratio 1 Rate Rate Todescribethefrequencyorintensionofsomephenomenon Numberofindividualoccurredsomethingwithinaperiodoftime Rate Thewholenumberoflikelytooccurredsomethinginthesameperiod Example1Toinvestigate8589oldpeopleinsomecityin1998 and2823peoplehadhypertension Morbidityrate 2823 8589 100 32 87 2 Proportion Proportion Todescribetheratioofnumberofonepartandthewholenumberinthesamething Formula 100 Numberofindividualsinonepart Proportion Thewholenumberofindividuals Example2Calculatethepatientsproportionof5diseasesinonehospitalin1990and1998 Example2Calculatethepatientsproportionsof5diseasesinonehospitalin1990and1998 Characteristics 1 Summationofproportionsinonethingis100 2 Proportionsinthesamethingareinteractional 3 Ratio Ratio thequotientoftworelatedindexsFormula 100 Aindex Ratio Bindex Example3Thereare370malenewbornsand358femalenewbornsinahospitalinoneyear thenThesexratioofnewbornbabies 370 358 100 103 Section2Applicationofrelativenumbers 1 Thedenominatorofrelativenumbershouldnotbetoosmall 2 Proportionshouldnotsubstituterate 3 Tocalculatethetotalratecorrectly 4 Comparisonofrelativenumbers5 Comparisonofsamplerate proportion shoulddohypothesistest Section3Standardizationofrate 1 DefinitionTocalculatestandardratebyuniforminteriorconstitute Standardization oradjustment ofratesisusedtoenablethevalidcomparisonofgroupsthatdifferregardinganimportanthealthdeterminant mostcommonlyage Itisinfactaspecificapplicationofthegeneralmethodstocontrolforconfoundingfactors 2 CalculationMethodDirectstandardizationIndirectstandardization Approach1 Choosethecorrectmethodbyconditionofdata 2 Choosestandardcomposing 3 Calculatestandardrate FormulaDirectstandardization Indirectstandardization Example4Tocalculatestandardcurerateoftwotherapeutics Approach 1 Diseasecurerateoftwotherapeuticsisknown Directstandardization2 Choosetotalpatientsnumberoftwotherapeuticsasstandard 3 Calculateanticipatedcurenumber 4 Calculatestandardcurerate 380 100 47 5 800 StandardcurerateofA 427 100 53 4 800 StandardcurerateofB Example5Aresearchinvestigatedoldwomen 776inthecityand789inCountryside Amongthem 322and335sufferedfromprimaryosteoporosis Thetotalmorbidityratesare41 5and42 5respectively Becausetheproportionsofageinurbanandruralareasofthisinvestigationformsaredifferent soweneedtostandardizethetwomorbidityrate 322 1 05 305 SMR Urbanstandardmorbidityratio 42 1 1 05 44 2 Urbanstandardmorbidityrate 335 0 95 353 SMR Ruralstandardmorbidityratio 42 1 0 95 40 0 Ruralstandardmorbidityrate Afterstandardization urbanmorbidityrateishigherthanrural 3 Application1 TheStandardizationonlyadapttothatinteriorformsaredifferentintwogroups andmayinfluencethecomparisonofrate 2 Becauseofdifferentchosenstandardpopulation standardizedratesaredifferenttoo So whilecomparingseveralstandardizedrates shouldadoptthesamestandardpopulation 3 Standardizedrateisnolongerthelocalreallevelatthattime itonlyshowstherelativelevelamongthecomparingmaterials 4 Thestandardizedratesoftwosamplesaresamplevalues thesamplingerrorexists Whencomparingthestandardizedratesoftwosamples weshoulddohypothesistestifthesamplesizeissmall Section4Dynamicseriesandanalysisindex Dynamicseries Aseriesofstatisticalindexarrangedintheorderoftime Toobserveandcomparechangesanddevelopmenttrendsintimeseries Theindexisasfollows absolutelyincreasingamount developmentspeedandgrowthrate averagedevelopmentspeedandaveragegrowthspeed Twoimportantelements time Statisticindex baselinereportedtimetheend Example6Table6showsthestatisticdataofoutpatientsamountinonehospitalfrom1991to1999 Toanalysebydynamicseries Table6Dynamicchangesofoutpatientsamount 1 Absolutelyincreasingamount theincreasingamounttotallytheincreasingamountyearbyyear Absolutelyincreasingamountexplainstheabsolutevaluethatthethingincreasesinaregularperiod 2 Developmentspeedandgrowthspeed Relativeratiowithfixedbase a1 a0 a2 a0 an a0 Ringra