最新HEARING LOSS IN AIRCRAFT MAINTENANCE TECHNICIANS：在飞机维修人员的听力损失教学讲义ppt.ppt

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1、HEARINGLOSSINAIRCRAFTMAINTENANCETECHNICIANS：在飞机维修人员的听力损失F111,aflyingfueltankDeseal,thenresealafueltankThefueltankswereaconfinedspaceTheywereverycramped,withtradespeoplecrawlingaroundthebracesMeasuringHearingThresholdsPure-toneaudiometryatthefrequencies

2、of0.5,1,2,3,4,6,8kHzforairconductionAustralianStandardAS1269.4.1998bytrainednursesMeasuresthresholddB(smallerisbetter)HearingThresholdresult:onepersonHearingThresholdresult:onepersonHowtocomparegroups?TreateachfrequencyseparatelyDo95%confidenceinterval

3、sforeachgroupoverlap?Mean(95%CI)HearingThresholdsDistributionofHearingThresholds:lowerfrequenciesDistributionofHearingThresholds:higherfrequenciesProblems16observationsonsinglepersonwillbecorrelatedDistributionheavilyskewedMultipletestcorrection(eg.Bon

4、ferroni)neededtocontroloverallerrorrateOtherfactorsneedtobecontrolledforAGE!TheISO-7029TheISO-7029:statisticaldistributionofhearingthresholdsasafunctionofageprovidesbygendertheexpectedmedianvalueofhearingthresholdsrelativetothemedianthresholdattheageof

5、18yearsandthestatisticaldistributionaboveandbelowthemedianvaluefortherangeofaudiometricfrequenciesfrom125Hzto8000Hzforpopulationsofotologicallynormalpersonsofgivenagebetween18and70yearsISO7029healthypop.:lowerfrequenciesISO7029healthypop.:higherfrequen

6、ciesQuantilemodel?Meanregression:coefficientsestimatedbyminimizingthesumofthesquaresoftheresidualsQuantileregression:coefficientsestimatedbyminimizingthesumoftheabsolutevaluesoftheresidualsQuantilemodel?Meanregression:1821GaussshoweditwasML,leastvarian

7、ceIFresidualsarenormal.Quantileregression:1818Laplaceshowedithadsmallervariancethanmeanforcertaindistributionswithlongtails.CentralLimitTheoremisnotacureall.StatisticalAnalysis:quantilemodeltocomparetonormalpopulationResponse:hearingthreshold(dB)Explan

8、atoryvariables:Frequency,AgePostingcategory,RankcategoryAlcoholconsumptioncategory,SmokingstatusDiabetesstatusSSRI’s(anti-depressants),malariamedicationRingingintheearsExposuregroup,civiliansolventexposureBootstrapstandarderrors:correla