摘要
目的:探讨应用Kaplan-Meier方法与bootstrap方法相结合处理膳食暴露评估中多个检出限存在时的未检出值数据.方法:以大米中的镉残留数据为例,应用Kaplan-Meier方法对数据拟合累积概率分布曲线,并且应用bootstrap方法估计残留值的均数和中位数的标准误以及累积概率的区间.结果:Kaplan-Meier方法处理多个检出限存在时的未检出值简单,便于计算机实现,Bootstrap估计的区间与近似估计区间一致性好.结论:对环境暴露评估中包含未检出值的左截尾数据的处理,结合bootstrap区间估计的Kaplan-Meier方法是值得推荐的有效方法.
AIM:To combine Kaplan-meier method and Bootstrap estimation in dealing with the left-censored data for exposure assessment. METHODS:The cumulative probability distribution for the cadmium residue concentration in rice was fitted by Kaplan-Meier method,basing on which standard errors and interval estimates of mean,median et al. were gained by bootstrap method. RESULTS:The Kaplan-Meier method can be used simply and conveniently by software. The intervals estimated by bootstrap were consistent with those by approximate method.CONCLUSION: Kaplan-Meier method combined with bootstrap is efficient method worth to recommend in dealing with data including left-censored values.
出处
《第四军医大学学报》
北大核心
2009年第21期2462-2464,共3页
Journal of the Fourth Military Medical University
基金
国家"十一五"科技支撑计划重大项目(2006BAK02A01)
江苏省卫生厅预防医学科研课题(Y200702)