Your manager is trying to determine what forecasting method to use. Based upon the following historical data, calculate the following forecast and specify what procedure you would utilize.

$\backslash$table$[[$MONTH$,$ACTUAL DEMAND$],[1,54],[2,57],[3,59],[4,64],[5,80],[6,81],[7,82],[8,83],[9,81],[10,85],[11,86],[12,86]]$

e$-1.$ Calculate the mean absolute deviation $($MAD$)$ for the forecasts made by each technique in periods $4-12.$ Note: Do not round intermediate calculations. Round your answers to $3$ decimal places.

$\backslash$table$[[,\backslash$table$[[$Mean Absolute$],[$Deviation$]]],[$Three$-$month moving average,$],[$Three$-$month weighted moving average,$],[$Single exponential smoothing forecast,$],[$Exponential smoothing with trend,$]]$