variance of population meaning in English

总体方差

The present methods for testing the large - scale corpus segmentation have the following faults : a . it is difficult to exactly estimating the variance of population ; b . the sampling quantity is too large to test the corpus segmentation . to solve the given problems , we put forward the testing method based on clustering , which sorts the sample of corpus into many group by clustering them
语料库分词质量的评价问题是汉语语料库的特有问题，已有的简单随机抽样的方法，当语料库规模变大时，无法精确估计分词质量评价中语料库样本的总体方差，同时，为了保证检验的精度，传统抽样方法的检验费用太高。
The following merits can gain by using the clustering method : a . the sampling quantity can be reduced by using the method to test the segmentation of the large - scale corpus ; b . the testing precision can be improved and the variance of population can be estimated more exactly
与已有的简单随机抽样方法相比，本文提出的方法在大规模语料库分词质量评价时，有如下优点； a通过聚类得到语料库抽样样本分词正确率的分层知识，进而在检验中运用分层抽样带来的增益减少检验的费用： b