Problem $12-2($Algo$)$

Given the series of demand data below

Period: $12345678910$

Demand: $44364940254040382741$

Click here for the Excel Data File

a$.$ Calculate the forecasts for periods $7$ through $11$ using moving average models with n $=2,$ n $=4,$ and n $=6.$

b$-1.$ Calculate the bias and MAD for each set of forecasts.

MAD FOR n:$2$ is $7\mathrm{.}5,$ for n:$4$ is $4\mathrm{.}2$ and for n:$6$ is $4\mathrm{.}8$

The only thing that I need to find is THE BIAS