In this paper it not only gives the method of unequal probability in group sampling and unbiassedness of mean estimation and also gives the variance and its unbiassedness of estimation.
本文给出了集团抽样的不等概方法和均值的无偏估计，同时也给出了这种估计的方差及方差的无偏估计。
In this paper it not only gives the method of unequal probability in group sampling and unbiassedness of mean estimation and also gives the variance and its unbiassedness of estimation.
本文给出了集团抽样的不等概方法和均值的无偏估计，同时也给出了这种估计的方差及方差的无偏估计。
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