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

Actual

Forecast

Error

$10$

$11$

$-1$

$8$

$10$

$-2$

$10$

$6$

$4$

$6$

$6$

$0$

$9$

$4$

$5$

$$

Question $4$Answer

a$.$

$2\mathrm{.}4$

b$.$

$6\mathrm{.}0$

c$.$

$1\mathrm{.}2$

d$.$

$-0\mathrm{.}2$

e$.$

$12\mathrm{.}0$