Summers S
J Post Anesth Nurs. 1991 Oct;6(5):355-8.
Sample selection is a very important but sometimes underestimated part of a research study. Sampling theory describes two sampling domains: probability and nonprobability. Probability samples contain some type of randomization and consist of simple, stratified, systematic, cluster, and sequential types. Nonprobability samples lack randomization and consist of convenience or accidental, purposive, quota, volunteer, and expert types. The primary distinction between the two domains is that the probability sampling study findings can be generalized to the target population while the nonprobability sampling study findings can only be generalized to the institution where the sample was studied.
样本选择是一项非常重要但有时会被低估的研究部分。抽样理论描述了两个抽样领域：概率抽样和非概率抽样。概率样本包含某种类型的随机化，由简单随机抽样、分层抽样、系统抽样、整群抽样和序贯抽样组成。非概率样本缺乏随机化，由便利抽样或偶遇抽样、立意抽样、配额抽样、志愿者抽样和专家抽样组成。这两个领域的主要区别在于，概率抽样研究的结果可以推广到目标人群，而非概率抽样研究的结果只能推广到进行样本研究的机构。
