$($SHOW YOUR COMPLETE WORK$)$ Two independent forecasting methods $1$ and $2$ have been used each week for the past eight weeks. The actual demand and demand forecasts from these two methods are shown below.

$\backslash$table$[[$WEEK$,\backslash$table$[[$ACTUAL DEMAND$],[($in units$)]],$DEMAND FORECASTS $($in units$)],[$Method $1,$Method $2],[$Eight weeks ago,$164,162,158],[$Seven weeks ago,$159,161,164],[$Six weeks ago,$158,157,161],[$Five weeks ago,$158,159,159],[$Four weeks ago,$161,160,161],[$Three weeks ago,$159,160,159],[$Two weeks ago,$161,160,160],[$One week ago,,$162,161]]$

a$.$ Calculate the Mean Absolute Deviation $($MAD$)$ measures for forecasting methods $1$ and $2.$ Which forecasting method is better based on MAD?

$[12$ points$]$

b$.$ Calculate the Mean Squared Error $($MSE$)$ measures for forecasting methods $1$ and $2.$ Which forecasting method is better based on MSE?

$[12$ points$]$

c$.$ Calculate the Mean Absolute Percent Error $($MAPE$)$ measures for forecasting methods $1$ and $2.$ Which forecasting method is better based on MAPE?

$[29$ points$]$