格拉布斯准则判断异常数据。格拉布斯检验法是在未知总体标准偏差的情况下，对正态样本或接近正态样本异常值进行判别的一种方法，是一种从理论上就很严密，概率意义明确，以经实验证明 效果较好的判据。具体方法如下：对一系列重复测量中的最大或最小数据，用格拉布斯检验法检验，若残差 v i max ? g? ? x ? ，则判断此值为异常数据，应予以剔除。(Grubbs test is a method to discriminate normal or normal samples under the condition of unknown overall standard deviation. It is a theory which is very strict and has a clear sense of probability. It is proved by experiment that the effect is better.)