What is a subset of a population used for in research?

A subset of a population is utilized in research primarily to represent the entire population when it is too large to study comprehensively. This approach allows researchers to draw conclusions based on the analysis of the smaller group, which should ideally reflect the characteristics of the larger group. By selecting a well-chosen sample, researchers can make inferences about the population without having to gather data from every individual, which can be time-consuming and resource-intensive.

Using a subset in this way also enhances the feasibility of research, ensuring that conclusions drawn are still valid and applicable to the broader population. A well-constructed sample provides insights into trends, behaviors, or preferences present in the larger group, thus making it an essential tool in various research methods.

The other choices, while related to aspects of research, do not encapsulate the primary function of a sample in the same way. A sample size refers to the number of participants involved but does not inherently reflect the role of representing the population. Focus groups are indeed a qualitative research method, but they are just one of many approaches to data collection and do not define the purpose of a sample. Collecting secondary data involves using existing data rather than gathering it from a subset of a population, which is a different process altogether.