Which term encompasses the entire class of subjects that a study aims to understand or analyze?

The term that encompasses the entire class of subjects that a study aims to understand or analyze is population. In research methodology, the population represents the complete set of individuals or items that share a common characteristic, and from which a sample may be drawn for the study. It is crucial to define the population accurately, as it directly impacts the validity and applicability of the study's conclusions.

A sample refers to a subset of the population selected for participation in the study and is used to make inferences about the larger group. Although samples are crucial for practical research, they are not the complete set of subjects.

Study design refers to the overall strategy and framework that guides how a research study is conducted, including the methodology, data collection, and analysis. While important, it does not refer to the subjects being studied.

Validation is the process of ensuring that the methods and instruments used in research accurately measure what they are intended to measure. It is an essential aspect of research quality, but it does not pertain to the population of subjects under investigation.

By understanding that the population includes all subjects relevant to a study, researchers can better ensure their findings are representative and applicable to the larger group.