Shanghai International Program for Development Evaluation Training Asia-Pacific Finance and Development Center; 200 Panlong Road-Shanghai, October 14, 2008

1. Deciding on the Sampling Strategy 决定抽样策略 Shanghai International Program for Development Evaluation Training Asia-Pacific Finance and Development Center 200 Panlong Road-Shanghai, October 14, 2008 Ray C. Rist

4. Introduction to Sampling 抽样简介

6. Sampling Concepts 抽样的概念

10. Types of Samples: Random and Non-Random 样本的类型：随机样本和 非随机样本

15. Stratified Random Sample 分层随机样本 Total Population www.dadangsolihin.com 总体 sub-popula-tion 子总体 Sub-population 子总体 sub-population 子总体 simple random sample 简单随机样本 simple random sample 简单随机样本 simple random sample 简单随机样本

22. Summary of Random Sampling Process 随机抽样过程概述 Step Process 步骤 过程 1 Obtain a complete listing of the entire population 取得总体的完整列表 2 Assign each case a number 对总体内的所有个体进行编号 3 Randomly select the sample using a random numbers table 使用随机数表随机地抽取样本 4 When no numbered listing exists or is not practical to create: 当不存在一个经过编号的列表或在操作上很难形成这样一个列表，则： • take a random start 随机地开始 • select every n th case 每隔 n 个个体选取一个作为样本

24. Types of Non-random Samples 非随机样本的种类 www.dadangsolihin.com whoever is easiest to contact or whatever is easiest to observe 最容易联系到的任何人，或最容易观察到的任何事 convenience 方便 set criteria to achieve a specific mix of participants 设定标准，来达到一个特定组合的参与者群体 purposeful (judgment) 目的明确 ask people who else you should interview 询问人们你还应该采访谁 Snowball 滚雪球效应

33. Sample Sizes for Large Populations 较大总体的样本容量 271 752 1,691 6,765 90% 384 1,067 2,401 9,604 95% 666 1,848 4,144 16,576 99% 5% 3% 2% 1% Confidence Level 置信区间 Precision 精确度

36. Thank you! 谢谢！