$($a$)$ Use 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 MSE?

$($b$)$ Use the Winter's method with smoothing constants $===0\mathrm{.}2$ to develop a forecast for

these data. How does it fit? What is the resulting MSE?

$($c$)$ Using Solver, find smoothing constants, for both forecasting methods, that minimize the MSE.

Comment on the fit of both models for the data in the third year.