Definition
Sample
A smaller part of a population selected for observation or measurement.
What it means
The population is the whole target group. A sample is the smaller part you actually collect data from. How the sample is chosen matters, because an easy or biased part may not tell the truth about the whole population.
Remember it
Sample means the small part studied; population means the whole group.
Example
A library has 2,000 books. To estimate how many need repair, staff randomly inspect 80 books. The 80 inspected books are the sample; all 2,000 books are the population.
Watch for
A group is not a useful statistical sample unless it comes from the target population and is chosen in a way suitable for the conclusion.
Common mix-up
The everyday meanings of sample—such as a taste, a music clip, or a specimen—do not automatically have the statistical population sense.
Exact meaning
In statistics, a sample is a subset of units selected from a population and observed or measured to learn about that population.