Selecting Research Participant. Sample & Population. A population is the entire set of individuals of interest to a researcher. A sample is a set of individuals selected from a population and usually is intended to represent the population in a research study. Selection bias.
The first principle is that a large sample is probably more representative than a small sample.
Although large samples are good, there is also a practical limit to the number of individuals that is reasonable to use in a research study.
33% available White
33% available Black
33% available Latino