A statistical model is used in applied statistics. Three basic notions are sufficient to describe all statistical models.
We choose a statistical unit which we will observe directly. Multiple observations of the same unit over time is called longitudinal research[?]. Observations of a variety of statistical attributes[?] is a common way of studying relationships among the attributes of a single unit.
We may really be interested in a statistical population (or set) of similar units rather than in any statistical unit per se. Survey sampling offers an example of this type of application.
... km² (5.6 mi²) of it is land and none of the area is covered with water.
Demographics
As of the census of 2000, there are 3,587 people, 1,445 households, and ...