We give the approximation formulas of the variance of the sample ratio estimator for a population mean and its asymptotically non-biased estimator in multi-stage sampling.

讨论多阶段抽样比率估计及其样本量选择的问题，给出了比率估计抽样均方误差的近似公式及其渐近无偏估计的公式。

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In this paper, the range glint is analyzed in theory through the model of sample ratio established, and then its physical essence is also expatiated using echo spectrum aberration.

本文通过所建立的采样比率模型对多目标的距离闪烁效应进行了理论分析，并从回波频谱畸变的角度解释了其物理本质。

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The bandwidth of target signal after stretch processing and narrowband filtering, the data sample ratio and computing burden are reduced greatly and the method is easy for engineering implementation.

经拉伸处理和窄带滤波的目标信号带宽大大降低，数据采样率也大大降低，因此计算量减小，利于工程实现。

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The figures are not strictly comparable, because sample surveys show the sex ratio at birth, whereas the census gives it among infants up to the age of six.

ECONOMIST: India's skewed sex ratio: Seven brothers | The

To be fair, Hulbert does note that he was looking at a small sample size and that there have been instances where the CAPE ratio has stayed at high levels before a bear market set in.

FORBES: Are Stocks Cheap Or Expensive?

Braun learned Oct. 19 his sample was positive for elevated testosterone, which he said was at a ratio that was the highest ever recorded in baseball's testing program.

WSJ: Ryan Braun, Milwaukee Brewers Slugger, Says 'Truth Prevailed' - MLB