Editing Statistical unit (section)

==Implementation==
In most statistical studies, the goal is to generalize from the observed units to a larger set consisting of all comparable units that exist but are not directly observed.  For example, if we randomly sample 100 people and ask them which candidate they intend to vote for in an election, our main interest is in the voting behavior of all eligible voters, not exclusively on the 100 observed units.

In some cases, the observed units may not form a sample from any meaningful population, but rather constitute a [[accidental sampling|convenience sample]], or may represent the entire population of interest.  In this situation, we may study the units [[descriptive statistics|descriptively]], or we may study their [[dynamic model|dynamics]] over time.  But it typically does not make sense to talk about generalizing to a larger population of such units.  Studies involving [[country|countries]] or [[business|business firms]] are often of this type. [[Clinical trial]]s also typically use convenience samples, however the aim is often to make inferences about the effectiveness of treatments in other patients, and given the inclusion and exclusion criteria for some clinical trials, the sample may not be representative of the majority of patients with the condition or disease.

In simple [[data]] sets, the units are in one-to-one correspondence with the data values.  In more complex data sets, multiple measurements are made for each unit.  For example, if blood pressure measurements are made daily for a week on each subject in a study, there would be seven data values for each statistical unit. Multiple measurements taken on an individual are not [[Independent and identically distributed random variables|independent]] (they will be more alike compared to measurements taken on different individuals). Ignoring these dependencies, the analysis can lead to an inflated sample size or [[pseudoreplication]].

While a ''unit'' is often the lowest level at which observations are made, in some cases, a ''unit'' can be further decomposed as a [[statistical assembly]].

Many statistical analyses use [[quantitative data]] that have [[units of measurement]].  This is a distinct and non-overlapping use of the term "unit."