This document discusses sampling and different sampling techniques. Sampling involves selecting a subset of units from a population to study and make generalizations about the larger population. The benefits of sampling include reduced costs, faster data collection, and greater flexibility in the types of information that can be obtained compared to a complete census. There are two main types of sampling techniques: probability sampling, where each unit has an equal chance of selection, and non-probability sampling, where units are selected non-randomly based on accessibility or the researcher's judgment.