Populations and samples

In everyday language, a population is usually all the people living in a country or a city or some other defined area. The word population comes from the word people, or rather the word populus which means people in Latin.

In Statistics, when we talk about a population, we mean something similar. The members of a population in Statistics may or may not be people though. The population could be test results or crabs or people or something else. The population is everybody or everything you want to find something out about.

Statistics are used to enable people to find things out about populations. Some\times, like in a census, questions are asked of the whole population but often it is too much work to ask the whole population we are interested in, so we ask, or measure, some of the population and use this information to make guesses about the whole population. The members of the population that we ask or measure are called a sample.