An Advanced Hybrid Forecasting System for Wind Speed Point Forecasting and Interval Forecasting

Table 4

The indexes for evaluating the prediction ability.

Metric	Definition	Equation
MAPE	The average of N absolute percentage error
MAE	The mean absolute error of N forecasting results
RMSE	The square root of the average of the error squares
MSE	Mean squared error
DC	Directional change
FICP	Forecast interval coverage probability
FINAW	Forecast interval normalized average width
AWD	Accumulated width deviation of testing dataset

In the formulas, L_i and U_i represent the lower and the upper limit of the production interval, respectively. And, c_i is the number of the truth value contained in constructed interval. N is the number of the testing set [16]. Data are the actual data. Besides, AWD_i is the width deviation of the construction interval of each sample.