Definicija: The mean error is an informal term that usually refers to the average of all the errors in a set. An “error” in this context is an uncertainty in a measurement, or the difference between the measured value and true/correct value. The more formal term for error is measurement error, also called observational error.

Definicija: measure of errors between paired observations expressing the same phenomenon. Examples of Y versus X include comparisons of predicted versus observed, subsequent time versus initial time, and one technique of measurement versus an alternative technique of measurement

Definicija: sample standard deviation of the differences between predicted and observed values, with results in the same unit of measure of observed values. It describes the degree of coincidence among measured and simulated data