第六章 抽样社会调查与研究方法课件.ppt

社会调查与研究方法 主讲：刘 杰 第六章 抽 样 §1 抽样的意义与作用 §2 概率抽样的原理与程序 §3 概率抽样方法 §4 户内抽样与PPS抽样 §5 非概率抽样 抽样是研究设计的主要内容之一，也是社会调查的一个重要步骤，它不仅与研究目的及研究内容紧密相关，而且还直接关系到资料的收集、整理与分析，同时它还涉及到整个研究的费用以及应用的范围。 在本章中，你们将了解 到社会科学家如何通过选择一小部分人进行研究，并将结论推及到千百万未被研究的人。 §1 抽样的意义与作用 抽样调查(Sampling survey) 运用一定的方法在调查对象总体中抽取一部分调查对象作为样本，并对样本调查结果来推断总体的方法 一、基本术语 元素（element） 元素是构成总体的最基本单位，是搜集信息的单位和进行分析的基础 Element An element is that unit about which information is collected and which provides the basis of analysis. Typically, in survey research, elements are people or certain types of people. However, other kinds of units can constitute the elements for social research; families, social clubs, or corporations might be the elements of a study. (Note: Elements and units of analysis are often the same in a given study, though the former refers to sample selection while the latter refers to data analysis.) 总体(population) 总体是构成它的所有元素的集合 总体通常与构成它的元素（Element)共同定义：总体是构成它的所有元素的集合，而元素则是构成总体的基本单位。（一个总体所包含的元素数常用大写字母 N 表示） Population A population is the theoretically specified aggregation of study elements. For example, specifying the term “college students” would include a consideration of full-time and part-time students, degree candidates and non-degree candidates, undergraduate and graduate students, and similar issues. 研究总体 研究总体是在理论上明确界定的个体的集合体 它必须受几个方面的限定： 内容、单位、范围、时间 Study Population A study population is that aggregation of elements from which the sample is actually selected. As a practical matter, you are seldom in a position to guarantee that every element meeting the theoretical definitions laid down actually has a chance of being selected in the sample. Even where lists of elements exist for sampling purposes, the lists are usually somewhat incomplete. Some students are always omitted, inadvertently, from student roster. Some telephone subscribers request that their names a