In science, measurement errors refer to the difference between the measured quantity value and its true or reference quantity value (Bell, 1999).

It is important to note that a scientific error is not a mistake in making the measurements.

What is the difference between an "error" and a "mistake"?

• An "error" can refer to the deviation of a measurement from its true value. Errors of measurement cannot be eliminated! They are not mistakes, they are limitations of the ability to measure.

• A "mistake" is fault, usually caused by a person, who did not do the thing which was intended.

In Science, we DO NOT accept "human error" as a valid reason for inconsistent data.

Generally, there are two classes of errors in measurement (Bell, 1999). [Note that errors of measurement should not be confused with statistical errors].

• Systematic errors

• Random errors