It is considered difficult to analytically prove whether sample probability weighted moments with discrete series are unbiased estimators.

人们普遍认为要从理论上通过数学分析的方法来论证不连序系列样本概率权重矩的偏倚性是很困难的。

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Experiments, Outcomes, Sample Spaces, Events, Probability, Axioms of Probability.

试验，结果，样本空间，事件，机率，机率公理。

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Because of the phenomenon that the negative self-scattering cross sections cause the negative probability sample, a nonnegative corrected method is put forward and validated by the benchmark problems.

针对输运修正引起的自散射截面导致的负概率抽样现象，提出了一种非负修正方法，并用基准计算验证了该方法的正确性。

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This online survey is not based on a probability sample and therefore no estimate of theoretical sampling error can be calculated.

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The monthly Consumer Confidence Survey, based on a probability-design random sample, is conducted for The Conference Board by Nielsen.

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Therefore, the convention among academic researchers is that it is ok, and you can claim your conclusion based on only a sample of observations, as long as the probability that you are wrong is no bigger than 5%.

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