Editing Margin of error (section)

{{Short description|Statistic expressing the amount of random sampling error in a survey's results}}
{{about|the statistical precision of estimates from sample surveys|observational errors|Observational error|safety margins in engineering|Factor of safety|tolerance in engineering|Engineering tolerance|the eponymous movie|Margin for error (film)}}
{{More footnotes needed|date=November 2021}}
[[File:Margin-of-error-95.svg|thumb|upright=1.4|[[Probability density function|Probability densities]] of polls of different sizes, each color-coded to its 95% [[confidence interval]]  (below), margin of error (left), and sample size (right). Each interval reflects the range within which one may have 95% confidence that the ''true'' percentage may be found, given a reported percentage of 50%. The ''margin of error'' is half the confidence interval (also, the ''radius'' of the interval). The larger the sample, the smaller the margin of error. Also, the further from 50% the reported percentage, the smaller the margin of error.]]

The '''margin of error''' is a statistic expressing the amount of random [[sampling error]] in the results of a [[Statistical survey|survey]]. The larger the margin of error, the less confidence one should have that a poll result would reflect the result of a simultaneous census of the entire [[Statistical population|population]]. The margin of error will be positive whenever a population is incompletely sampled and the outcome measure has positive [[variance]], which is to say, whenever the measure ''varies''.

The term ''margin of error'' is often used in non-survey contexts to indicate [[observational error]] in reporting measured quantities.