# Population proportion

A part of a population with a particular attribute, expressed as a fraction, decimal or percentage of the whole population.

For a finite population, the population proportion is the number of members in the population with a particular attribute divided by the number of members in the population.

In many real situations the whole population is not available to be checked for the presence of an attribute. In such cases the value of the population proportion is not known. The population proportion may be estimated by taking a random sample from the population, calculating the sample proportion and using this value as an estimate of the population proportion.

The population proportion is a number representing a part of a population and is therefore an example of a population parameter.

The Greek letter π (pi) is a common symbol for the population proportion.

See: proportion

**Curriculum achievement objectives references**

Statistical investigation: Levels (7), (8)