After reading this chapter, you should be able to:

1. Explain why researchers select samples that are representative of a population of interest.
2. Distinguish between subjects and participants as terms used to describe those who are subjected to procedures in a research study.
3. Distinguish between probability sampling methods and nonprobability sampling methods.
4. Delineate two nonprobability sampling methods: convenience sampling and quota sampling.
5. Delineate four probability sampling methods: simple random sampling, stratified random sampling, systematic sampling, and cluster sampling.
6. Define and explain sampling error and the standard error of the mean.
7. Define and explain sampling bias and nonresponse bias.
8. Identify potential ethical concerns related to sampling at schools.