Population proportion

A population proportion, generally denoted by ${\displaystyle P}$ and in some textbooks by ${\displaystyle \pi }$, is a parameter that describes a percentage value associated with a population. For example, the 2010 United States Census showed that 83.7% of the American Population was identified as not being Hispanic or Latino. The value of .837 is a population proportion. In general, the population proportion or any other population parameter is unknown. A census can be conducted in order to determine the actual value of a population parameter, but in most statistical practices, a census is not a practical method due to its costs and time consumption.

A population proportion is usually estimated through an unbiased sample statistic obtained from an observational study or experiment. For example, the National Technological Literacy Conference conducted a national survey of 2,000 adults to determine the percentage of adults who are economically illiterate. The study showed that 72% of the 2,000 adults sampled did not understand what a gross domestic product is. The value of 72% is a sample proportion. The sample proportion is generally denoted by ${\displaystyle {\hat {p}}}$ and in some textbooks by ${\displaystyle p}$.

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