Learning Objectives

5.1 Summarize the process of probability-based sampling
5.2 Describe the circumstances that make sampling unnecessary and the reasons they are rare
5.3 Explain why probability-based sampling is needed to obtain a representative sample
5.4 Define the different probability sampling methods
5.5 Defend the value of nonprobability sampling methods
5.6 Assess how sampling error is affected by sample size, the heterogeneity of the population, and the fraction of the population included in the sample