In statistics, a population is a set of similar items or events which is of interest for some question or experiment. A common aim of statistical analysis is to produce information about some chosen population. If a sample is chosen properly, characteristics of the entire population that the sample is drawn definition of population in statistics pdf can be estimated from corresponding characteristics of the sample.
A subconcept of a population that shares one or more additional properties is called a subpopulation. By contrast, a sample is a subset of a population that is not chosen to share any additional property. Descriptive statistics may yield different results for different subpopulations. For instance, a particular medicine may have different effects on different subpopulations, and these effects may be obscured or dismissed if such special subpopulations are not identified and examined in isolation.
Similarly, one can often estimate parameters more accurately if one separates out subpopulations: the distribution of heights among people is better modeled by considering men and women as separate subpopulations, for instance. Populations consisting of subpopulations can be modeled by mixture models, which combine the distributions within subpopulations into an overall population distribution.
If sufficiently separated, these form a bimodal distribution, otherwise it simply has a wide peak. Further, it will exhibit overdispersion relative to a single normal distribution with the given variation. Glossary of statistical terms: Population”. Glossary of statistical terms: Sample”.
Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. This article lists the most populous cities in the world defined according to a concept of city proper. A city proper is a locality defined according to legal or political boundaries and an administratively recognised urban status that is usually characterised by some form of local government.
Cities proper and their boundaries and population data may not include suburbs. World Urbanization Prospects, a UN publication, defines population of a city proper as “the population living within the administrative boundaries of a city or controlled directly from the city by a single authority. The book continues to say that “city proper as defined by administrative boundaries may not include suburban areas where an important proportion of the population working or studying in the city lives.