产前筛查试验中MOM方法的原理及其应用

Principles and applications about the MOM in prenatal screening

目的系统地介绍MOM(Multiplesofthemedian)方法的原理、目的、前提条件及其使用效果的检验方法。方法从MOM方法分析的目的入手,结合分析过程中的每一步骤,讨论MOM转换必须满足的统计前提及所得统计学结论。结果MOM方法在一定的条件下可以消除影响因素对指标的影响,从而可以达到将不同的样本混合在一起的目的。结论MOM方法适用的资料是测量值在整个范围内是一种等比例变化关系,不同的样本经MOM转换后能混合在一起的前提条件是,转换成MOM后不同样本的变异系数近似为一常数。MOM方法使用效果检验,一是看其对影响因素的消除效果,另外就是看混合后样本的正态拟合优度。

Objective To introduce the method of MOM about the principles, purposes, premises and the test methods for its performance. Methods We begin with the purposes of the MOM, analyze the statistical premises and conclusions in the processing steps. Results The MOM method can remove the influences that the influencing factors impact on the essays under some postulates and the different samples can be mixed together for one. Conclusion The MOM is suit for the data that different samples vary with the constant proportion in different percentages. The premise upon which the different MOM can be mixed together is that the coefficients of variation （CV） in different MOM is constant. The one for testing the MOM performances is examining the elimination for the influences, the other one is the goodness of normality for the mixed sample.