Define mean absolute error.

Explanation

The arithmetic mean of all the absolute errors of measurement is called mean absolute error.
Let `Deltax_(1)`, `Deltax_(2)`,…………, `Deltax_(n)` be the absolute errors, then mean absolute error is given by
`Deltabarx=(|Deltax_(1)|+|Deltax_(2)|+.....+|Deltax_(n)|)/(n)=(1)/(n)sum_(i=1)^(n)|Deltax_(i)|`