What is the term referring to a group of people participating in a research study?

The term that refers to a group of people participating in a research study is "Sample." In research methodology, a sample is a subset of a population that is selected for the actual study. Researchers use samples to gather data and test hypotheses when studying entire populations would be impractical or impossible.

The selection of a sample is crucial because it needs to be representative of the population to ensure that the findings can be generalized to the larger group. Sampling methods can vary, including random sampling, stratified sampling, and convenience sampling, each having its advantages and implications for the study's validity.

In contrast, the other terms listed refer to broader or different contexts. The term "population" denotes the entire group from which a sample is drawn. A "group" is a more general term that does not imply any specific selection criteria for research. A "control group" specifically refers to a subset of participants that is not exposed to the experimental treatment, used for comparison purposes against those who are exposed to the treatment.