Required Statistics:

Standard Deviation

Consider a population consisting of the following eight values:

These eight data points have the mean (average) of 5:

To calculate the population standard deviation, first compute the difference of each data point from the mean, and square the result of each:

Next compute the average of these values, and take the square root:

Mean Squared Error
See Mean Squared Error on Wikipedia

Absolute Error
Given some value v and its approximation vapprox, the absolute error is

where the vertical bars denote the absolute value. If the relative error is

Relative Error

and the percent error is

These definitions can be extended to the case when v and vapprox are n-dimensional vectors, by replacing the absolute value with an n-norm.[1]

Last edited Apr 18, 2011 at 12:33 AM by sesmar, version 1