In repeated sampling of a time varying population, the use of previous survey results can improve the present survey results or save the survey costs.

对一个时变总体进行经常性调查时，利用前次查的结果，可以提高本次调查结果的精度，节省调查的费用。

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In repeated sampling of a time varying population, the use of previous survey results can improve the present survey results or save the survey costs.

对一个时变总体进行经常性调查时，利用前次查的结果，可以提高本次调查结果的精度，节省调查的费用。

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