A **statistic** (singular) is a single measure of some attribute of a sample (e.g., its arithmetic mean value). It is calculated by applying a function (statistical algorithm) to the values of the items of the sample which are known together as a set of data.

More formally, statistical theory defines a **statistic** as a function of a sample where the function itself is independent of the sample's distribution; that is, the function can be stated before realization of the data. The term statistic is used both for the function and for the value of the function on a given sample.

A statistic is distinct from a statistical parameter, which is not computable because often the population is much too large to examine and measure all its items. However, a statistic, when used to estimate a population parameter, is called an **estimator**. For instance, the *sample mean* is a statistic which estimates the *population mean*, which is a parameter.

Read more about Statistic: Examples