$(1)$ Please use the following two methods to forecast the quarterly demand for year $6$:

$$ Four$-$period Moving Average

$$ Winter Model $($Assume the smoothing parameters alpha $=0\mathrm{.}1,$ beta $=0\mathrm{.}1,$ gamma $=0\mathrm{.}1)$

$(2)$ For each of the forecasting methods, estimate the mean absolute deviation $($MAD$)$ of your forecast error in years $1-5.$

$(3)$ Which method is more accurate? Why?