Experimental error

Statistics
In statistics, an error is a difference between a computed, estimated, or measured value and the true, specified, or theoretically correct value. See errors and residuals in statistics.

Experimental science
An error is a bound on the precision and accuracy of the result of a measurement. These can be classified into two types: statistical error (see above) and systematic error. Statistical error is caused by random (and therefore inherently unpredictable) fluctuations in the measurement apparatus, whereas systematic error is caused by an unknown but nonrandom fluctuation. If the cause of the systematic error can be identified, then it can usually be eliminated. Such errors can also be referred to as uncertainties.