除了样本误差外，全国性的公众意见的调查操作上的困难也会导致误差。

In addition to sampling error, the practical difficulties of conducting any survey of public opinion may introduce other sources of error into the poll.

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研究结果是基于1990年后的一个全国性的男性女性测验样本，这些样本具备相当的同质性。

Said the study builds upon research in the 1990s that tested similar patterns in a national sample of working women and men.

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我们用1992年至2001年全国性的患者作为样本，确定其初始诊断、手术方法和相关的院内并发症和死亡率。

Using the Nationwide Inpatient Sample, we determined the primary diagnoses, surgical procedures, and associated in-hospital complications and mortality from 1992 to 2001.

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我们用1992年至2001年全国性的患者作为样本，确定其初始诊断、手术方法和相关的院内并发症和死亡率。

Using the Nationwide Inpatient Sample, we determined the primary diagnoses, surgical procedures, and associated in-hospital complications and mortality from 1992 to 2001.

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