Forecast Accuracy $(10$ points$)$

Explain the definition of MAD $($Mean Absolute Deviation$),$ MSE $($Mean Squared Error$),$ and MAPE $($Mean Absolute Percent Error$)$ and compute MAD, MSE, and MAPE for the following data, showing actual and forecasted numbers of accounts serviced.

$\backslash$table$[[$Period$,$Actual,Forecast,A$-$F $($Error$),|||$ Error $|||,$Error ${?}^2,[\frac{|\text{E}\text{r}\text{r}\text{a}\text{r}|}{\text{A}\text{c}\text{t}\text{u}\text{r}\text{i}}],=100(\%)$