The following represents the demand for Sellers Ltd for a five months period Month Actual Demand Forecast $100200300400500$ Calculate : the forecast for period $2$ to $5$ using exponential smoothing method. Use a smoothing constant of $0\mathrm{.}4$ i$.$e$.\backslash$alpha $=0\mathrm{.}4.$ Assume the forecast for month $1$ is $100.$ the MAD, MSE and the MAPE using the forecast data determine the tracking signal $.$ Is this a good forecast if the control limit is $\backslash$pm $3?$