This document discusses population and sampling concepts for research. It defines a population as the complete set of people or objects with a common characteristic of interest. The target population is the entire group the researcher wishes to generalize to, while the accessible population includes cases that meet criteria and are available. A sample is a representative subset of the target population selected using sampling principles like random selection and large sample sizes to make inferences about the population. The key difference between a population and sample is that a population includes all elements while a sample is a subset used to study characteristics of the larger population.