A population is the complete set of items being studied.
A sample of a population is a part of the population. A sample is useful when you want to find out about a population, but you do not have the resources to study every member of the population.
Each member in the sample is called a subject.
Example Understanding Populations and Samples
You are investigating the lengths of all of the words in a book. Determine whether each description is a population or a sample.
a. All of the words on a page of the book
b. Every other word in the book
c. All of the words in the book
d. One word in the book