Residual Test: $\text{MAPE}=\frac{1}{n-1}{\displaystyle {\sum }_{k=2}^n\frac{\left|ϵ\left(k\right)\right|}{x^{\left(0\right)}\left(k\right)}\times 100}$

Criteria (MAPE)

Interpretation

<10%

High forecasting accuracy

10% - 20%

Good forecasting accuracy

20% - 50%

Reasonable forecasting accuracy

>50%

Weak and inaccurate predictability