Identify the Formula Used to Calculate the Root Mean Square $\sqrt { \frac { \sum _ { t = 1 } ^ { n } \left| A _ { t } - F _ { t } \right| } { n } }$

Multiple Choice

Identify the formula used to calculate the root mean square error over a range of forecasted values, if the actual value of the time series at time t and the forecast value for time t are denoted by At and Ft respectively.

A) RMSE = $\sqrt { \frac { \sum _ { t = 1 } ^ { n } \left| A _ { t } - F _ { t } \right| } { n } }$

B) RMSE = $\sqrt { \frac { \sum _ { t = 1 } ^ { n } \sqrt { \left| A _ { t } - F _ { t } \right| } } { n } }$

C) RMSE = $\sqrt { \frac { \sum _ { t = 1 } ^ { n } \left( A _ { t } - F _ { t } \right) ^ { 2 } } { n } }$

D) RMSE = $\sqrt { \frac { \sum _ { t = 1 } ^ { n } \left| \frac { A _ { t } - F +{ t } } { 2 } \right| } { n } }$