A forecasting method has produced the following over the past five months. What is the mean absolute deviation?

Actual

Forecast

Error

$|$Error$|$

$10$

$11$

$-1$

$1$

$8$

$10$

$-2$

$2$

$10$

$8$

$2$

$2$

$6$

$6$

$0$

$0$

$9$

$8$

$1$

$1$

A$.$

$0\mathrm{.}0$

B$.$

$-0\mathrm{.}2$

C$.$

$8\mathrm{.}6$

D$.$

$-1\mathrm{.}0$

E$.$

$1\mathrm{.}2$