In statistics, what is defined as the sample?

In statistics, the term "sample" specifically refers to the members of a group who are actually observed or consulted during a study. This subset is selected from a larger population and is used to draw conclusions about the entire population without needing to gather data from every individual within it. The primary goal of using a sample is to represent the population effectively while minimizing the time, cost, and effort involved in data collection.

When researchers design a study, they often cannot study the whole population due to constraints such as time or resources. Therefore, they select a sample that is hoped to be representative of that population, allowing for statistical inferences to be made based on the findings from the sample. If the sample is chosen correctly, it can provide valuable insights that can be generalized to the whole population.

The other options reflect different concepts within statistics. The entire population being studied refers to every member of the group that could be analyzed, which is distinct from the sample. The summary of all collected data describes statistical measures or results derived from data, not the sample itself. A hypothetical group used for testing is often related to theoretical constructs, such as in simulations or experiments that are not directly tied to empirical data collection, which is different from the purpose of a sample in research