# Observational Error

(Redirected from Measurement Uncertainty)

An Observational Error is an error in an observation/measurement.

## References

### 2016

• (Wikipedia, 2016) ⇒ https://en.wikipedia.org/wiki/Observational_error#Random Retrieved:2016-5-23.
• Observational error (or measurement error) is the difference between a measured value of quantity and its true value.[1] In statistics, an error is not a "mistake". Variability is an inherent part of things being measured and of the measurement process.

Measurement errors can be divided into two components: random error and systematic error. Random errors are errors in measurement that lead to measurable values being inconsistent when repeated measures of a constant attribute or quantity are taken. Systematic errors are errors that are not determined by chance but are introduced by an inaccuracy (as of observation or measurement) inherent in the system. [2] Systematic error may also refer to an error having a nonzero mean, so that its effect is not reduced when observations are averaged.

1. Dodge, Y. (2003) The Oxford Dictionary of Statistical Terms, OUP. ISBN 0-19-920613-9

### 2013

• http://en.wikipedia.org/wiki/Measurement_uncertainty
• In metrology, measurement uncertainty is a non-negative parameter characterizing the dispersion of the values attributed to a measured quantity. The uncertainty has a probabilistic basis and reflects incomplete knowledge of the quantity. All measurements are subject to uncertainty and a measured value is only complete if it is accompanied by a statement of the associated uncertainty. Relative uncertainty is the measurement uncertainty divided by the measured value.