The terms 'population' and 'sample' are important in statistics and refer to key concepts that are closely related.
Population: Everything in the group that we want to learn about.
Sample: A part of the population.
Examples of populations and a sample from those populations:
| Population | Sample |
|---|---|
| All of the people in Germany | 500 Germans |
| All of the customers of Netflix | 300 Netflix customers |
| Every car manufacturer | Tesla, Toyota, BMW, Ford |
For good statistical analysis, the sample needs to be as "similar" as possible to the population. If they are similar enough, we say that the sample is representative of the population.
The sample is used to make conclusions about the whole population. If the sample is not similar enough to the whole population, the conclusions could be useless.
Note: Many words have specific meanings in statistics.
The word 'population' normally refers to a group of people. In statistics, it is any specific group that we are interested in learning about.