Having a larger sample size boosts the generalizability of the study to the population.

New Mexico Highlands University

In research, the sample is studied with the goal of generalizing the results to the broader population from which the sample was drawn. This process allows researchers to make inferences about a large group based on data collected from a smaller, representative subset. The relationship is visually comparable to extracting a small representative group from a vast crowd.

Relationship Between Sample and Population

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020, April 22). Psychology (2nd ed.). OpenStax. https://openstax.org/books/psychology-2e/pages/1-introduction

OpenStax Psychology (2nd ed.) Textbook

Increasing Generalizability of the Sample

For a hypothetical experiment involving algebra students, the population of interest must first be defined. A broad population, such as 'all algebra students,' is often too large for a study. Therefore, it is narrowed to a more specific and manageable group, like 'all algebra students in a particular city.' To ensure the sample is representative, it should include students from diverse backgrounds, encompassing various income levels, family situations, races, ethnicities, religions, and geographic locations. From this more focused population, a random sample, for instance of 200 students, can be selected for the experiment.

Example of Defining a Population and Sample for Research

A team of researchers wants to determine the average screen time of all high school students in a large country. They conduct a detailed survey with 1,000 students from a single, affluent suburban high school known for its technology-rich classrooms. What is the most significant methodological challenge the researchers face when trying to draw a conclusion about the entire country's high school student population from their data?

Sampling bias is a systematic error that occurs when the method used to select participants results in a sample that fails to accurately represent the broader target population. Because the selected individuals differ in important ways from the overall group, any statistical findings derived from this unrepresentative sample will likely be inaccurate and cannot be safely generalized.

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