component of measurement error that in replicate measurements varies in an unpredictable manner
NOTE 1 A reference quantity value for a random measurement error is the average that would ensue from an infinite number of replicate measurements of the same measurand.
NOTE 2 Random measurement errors of a set of replicate measurements form a distribution that can be summarized by its expectation, which is generally assumed to be zero, and its variance.
NOTE 3 Random measurement error equals measurement error minus systematic measurement error.