A sample is a selection of people or objects that are representative of a population. Based on those surveyed as a sample we draw conclusions about the population as a whole.
It is a prerequisite for a statistically meaningful result that the sample, e.g. 2,000 Americans who were questioned on the phone will be a representative cross-section of, for example, all adult Americans over 21 years of age.
Please note that the definitions in our statistics encyclopedia are simplified explanations of terms. Our goal is to make the definitions accessible for a broad audience; thus it is possible that some definitions do not adhere entirely to scientific standards.