Based on the standard deviation and variation coefficient, soil water change in the profile could be divided into four layers by cluster analysis.
基于标准差和变异系数两个指标，采用聚类分析，可将土壤剖面水分垂直变化划分为四个层次：速变层、活跃层、次活跃层和相对稳定层。
The normal population characteristics, such as the mean, standard deviation, percentile, percentage and coefficient of variation, are often tested in engineering.
正态母体特征值（母体均值、百分位值、百分率、标准差和变异系数等）的检验是工程中常见的问题。
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