$b.$ Use an exponential smoothing with a linear trend model with smoothing constants $==0\mathrm{.}2$ to develop a forecast for these data. How does it fit? What is the resulting MSD$?$ Develop a graph for both $f(t)$ and $A(t)$ with Quarter on the $x-$axis and Demand on the y$-$axis.

$\backslash$table$[[$Year$,$Quarter,Demand,$F(t),T(t),f(t),$Difference$],[1996,1,25,25,0,-,-],[2,120,,,,],[3,40,,,,],[4,60,,,,],[,1,30,,,,],[,2,140,,,,],[,3,60,,,,],[,1,80,,,,],[,2,35,,,,],[,3,55,,,,]]$