Which of the following best defines a sample?

A sample is defined as a portion of a population selected for analysis, making it a subset that is used to make inferences about the larger group. It allows researchers to gather insights without needing to examine every member of the population, which can often be impractical or impossible. By focusing on a representative sample, statisticians can apply statistical methods to draw conclusions and make predictions while acknowledging the variability that exists within the entire population.

In research, the selection of a sample is crucial because it needs to accurately reflect the characteristics of the population to ensure that the findings are valid and applicable. Sampling methodologies, such as random sampling or stratified sampling, help to mitigate biases and improve the reliability of the results. This concept underscores the fundamental practice in statistics where detailed analysis of a subset can inform about the broader context.