Compute inflation rate for Jan $2018$ using exponential smoothing with contraint $-\mathrm{.}4$ and b$)$ with $.8$ Assume forecast for Jan $2017$ is $2\mathrm{.}5$

What is the MAD for the forecasts generated using exponential smothing method with $\mathrm{.}4$ and $\mathrm{.}8$ use only the months from March to December

c$)$ Which forecast is better? $$