Random Error
An error that varies unpredictably in size and direction between repeated measurements.
Unit
Various
In depth
Also called indeterminate error, it arises from countless small uncontrolled variations and follows a normal distribution. It affects precision rather than accuracy, and averaging n measurements reduces its effect on the mean by a factor of the square root of n.
Examples in the real world
Small variations in judging the meniscus or the exact end point colour from one titration to the next.