4 Types of Random Error

John Spacey, August 30, 2018

Random error are variations in measurements that occur when you are ostensibly measuring the same thing. This can be estimated using the variations between repeated measurements and reduced by averaging these measurements. The following are common types of random error.

Observer

Variations in the observer such as a researcher or instrument. For example, an extremely precise scale that outputs slightly different readings for the weight of an object weighed four times in succession.

Uncontrolled Variables

Variables beyond the control of an experiment that introduce variation into measurements. For example, uncontrolled barometric air pressure that changes throughout the day causing minor disturbances to sensitive measurements.

Controlled Variables

Minor variations in variables that are controlled. For example, a lab that is kept at 25°C that actually varies between 24.9°C and 25.1°C due to the activity of air conditioning units.

Random Variation

Outcomes that are influenced by variations that are fundamentally probabilistic. For example, computers are known to make errors due to interference from cosmic radiation. As such, a calculation that requires a large number of data processing steps to be precise and accurate may be run multiple times to confirm the calculation.

Overview: Random Error
Type	Experimental Error
Definition	Errors in measurement caused by factors that vary from one measurement to another.
Related Concepts	Experimental Error » Experiment Control » Experiment » Experiment Variables » Data Processing »