This episode introduces fundamental concepts in sociological research. It begins by explaining the necessity of sampling in sociological studies, detailing both probability sampling (such as random, systematic, and stratified methods) and non-probability sampling (including quota, snowball, and purposive techniques), each designed to select a representative group from a larger population. Furthermore, the text clarifies two critical criteria for evaluating research: reliability, which refers to the consistency and replicability of research findings, and validity, which addresses the accuracy of the research in measuring what it intends to measure. The host emphasises that understanding these concepts is crucial for assessing any sociological inquiry.