Find the Error $($E$)$ in Period $12.$ Using the trend adjusted model above, with the alpha and beta values provided, develop a forecast for period $18.7.$ Using the data in the model, develop a six period moving average for period $20.8.$ Using the data in the model, develop a forecast for period $16$ using a weighted moving average model with weights of $0\mathrm{.}5,0\mathrm{.}3,0\mathrm{.}2($with the first weight on the most recent data$).9.$ Calculate a bias based on periods $4$ to $8.10.$ Caluculat a tracking signal based on periods $5$ to $9.$