Random

Means that the error in a measured value is considered to be a stochastic independent draw from an underlying probability distribution; “random” implies in this context both “unpredictable” and “uncorrelated across measurements”; random errors therefore tend to “average out” across many measured values; random effects may be operating at the same time as other types of effect, in which case only a component of the total error is random; an example of a random effect (an effect giving rise to random errors) is electronic noise in an amplifier circuit.