1.1 本指南涵盖了环境采样中代表性的定义，确定了可能影响代表性（尤其是偏差）的来源，并描述了代表性样本或代表性样本集应具备的属性。为方便起见，本指南中使用术语“代表性样本”来表示代表性样本和代表性样本集，除非文中另有限定。 1.2 本指南概述了从人群中获得代表性样本的过程。代表性样本的目的是提供有关其成分（例如铅）的某些特征（例如浓度）的人口统计参数（例如平均值）的信息。该过程包括以下阶段:( 1. )在采集物理样本时，最小化采样偏差并优化精度( 2. )在分析物理样本以获取数据时，最小化测量偏差并优化精度，以及( 3. )从样本数据到总体进行推断时，最小化统计偏差。虽然本指南涵盖了偏差和精度，但重点是减少偏差。 1.3 本指南描述了代表性样本的属性，并介绍了获取代表性样本的一般方法。然而，它没有提供具体或全面的抽样程序。用户有责任确保使用适当和充分的程序。 1.4 本指南不包括对样本代表性的评估，因为不可能知道人口的真实价值。 1.5 由于每个采样事件的目的都是唯一的，因此本指南不试图给出步骤- 逐步说明如何制定抽样设计，以收集代表性样本。 1.6 附录X1 包含两个案例研究，讨论获得代表性样本的因素。 1.7 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 本指南定义了代表性样本的含义，以及样本需要具备的属性，以便从样本数据向总体提供有效推断。 4.2 本指南还提供了一个识别误差源（系统性和随机性）的过程，以便努力控制或最小化这些误差。这些来源包括采样误差、测量误差和统计偏差。 4.3 当目标仅限于采集代表性（物理）样本或代表性（物理）样本集时，只需考虑潜在的采样误差。当目标是从样本数据推断到总体时，需要考虑额外的测量误差和统计偏差。 4.4 本指南不适用于研究目标规定采集非代表性样本的情况。 在这种情况下，可以采取判断抽样或偏差抽样等抽样方法。这些方法不在本指南的范围内。 4.5 遵循本指南并不保证获得代表性样品。但是，如果不遵循此指南，可能会导致获取有偏见或不精确的样本数据，或者两者兼而有之。遵循本指南应提高从样本数据推断到总体的置信度。 4.6 本指南可与DQO过程结合使用（参见实践 D5792 ). 4.7 本指南适用于管理、设计和实施废物管理和受污染介质采样和分析计划的人员。

1.1 This guide covers the definition of representativeness in environmental sampling, identifies sources that can affect representativeness (especially bias), and describes the attributes that a representative sample or a representative set of samples should possess. For convenience, the term “representative sample” is used in this guide to denote both a representative sample and a representative set of samples, unless otherwise qualified in the text. 1.2 This guide outlines a process by which a representative sample may be obtained from a population. The purpose of the representative sample is to provide information about a statistical parameter(s) (such as mean) of the population regarding some characteristic(s) (such as concentration) of its constituent(s) (such as lead). This process includes the following stages: ( 1 ) minimization of sampling bias and optimization of precision while taking the physical samples, ( 2 ) minimization of measurement bias and optimization of precision when analyzing the physical samples to obtain data, and ( 3 ) minimization of statistical bias when making inferences from the sample data to the population. While both bias and precision are covered in this guide, major emphasis is given to bias reduction. 1.3 This guide describes the attributes of a representative sample and presents a general methodology for obtaining representative samples. It does not, however, provide specific or comprehensive sampling procedures. It is the user's responsibility to ensure that proper and adequate procedures are used. 1.4 The assessment of the representativeness of a sample is not covered in this guide since it is not possible to ever know the true value of the population. 1.5 Since the purpose of each sampling event is unique, this guide does not attempt to give a step-by-step account of how to develop a sampling design that results in the collection of representative samples. 1.6 Appendix X1 contains two case studies which discuss the factors for obtaining representative samples. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 This guide defines the meaning of a representative sample, as well as the attributes the sample(s) needs to have in order to provide a valid inference from the sample data to the population. 4.2 This guide also provides a process to identify the sources of error (both systematic and random) so that an effort can be made to control or minimize these errors. These sources include sampling error, measurement error, and statistical bias. 4.3 When the objective is limited to the taking of a representative (physical) sample or a representative set of (physical) samples, only potential sampling errors need to be considered. When the objective is to make an inference from the sample data to the population, additional measurement error and statistical bias need to be considered. 4.4 This guide does not apply to the cases where the taking of a nonrepresentative sample(s) is prescribed by the study objective. In that case, sampling approaches such as judgment sampling or biased sampling can be taken. These approaches are not within the scope of this guide. 4.5 Following this guide does not guarantee that representative samples will be obtained. But failure to follow this guide will likely result in obtaining sample data that are either biased or imprecise, or both. Following this guide should increase the level of confidence in making the inference from the sample data to the population. 4.6 This guide can be used in conjunction with the DQO process (see Practice D5792 ). 4.7 This guide is intended for those who manage, design, and implement sampling and analytical plans for waste management and contaminated media.