Population
Population is every unit in the group under study — all households, firms, or transactions relevant to the research question. Because observing the entire population is rarely possible, researchers draw a smaller subset called a sample.
See it move
The infographic is a two-column comparison placing the population against the sample. The population encompasses all N units, described by parameters μ and σ², and is rarely observable in full — illustrated with all German firms in 2024. The sample is a subset of n observations drawn from that population, described by statistics x̄ and s², and directly measurable — illustrated with 300 randomly selected firms; a random sample generalises to the population, but a convenience sample may not.
Check yourself
A food safety agency wants to know the average salt content per 100 g in all crisps sold in France. It tests 120 randomly selected packets from different brands. What is the population in this study?