样本追加是抽样调查的现实需求，也是一个抽样技术难题。

Sample complementing is the practical demand of sampling survey, and its also a difficult problem in sampling technology.

youdao

样本追加是抽样调查的现实需求，也是一个抽样技术难题。

Sample complementing is the practical demand of sampling survey, and its also a difficult problem in sampling technology.

youdao