StATS: What is a statistic?

A statistic is a number computed from a sample. Contrast this with the definition of a parameter. If a statistic is computed from a random sample (as is typically the case), then it has random variation or sampling error. An example of a statistic would be:

• the average length of stay in the birth hospital for a random sample of 387 infants born in Johnson County, Kansas.

This page was written by Steve Simon while working at Children's Mercy Hospital. Although I do not hold the copyright for this material, I am reproducing it here as a service, as it is no longer available on the Children's Mercy Hospital website. Need more information? I have a page with general help resources. You can also browse for pages similar to this one at Category: Definitions, Category: Hypothesis testing.