increase their fleet size or not. Since their ultimate objective is to satisfy the certain percentage of nationwide transportation demand, they obtained the following data representing total transportation demand in billions of dollars. $($You can copy tables into Excel$)$

Table $1.$ Demand for transportation

Source: U$.$S$.$ Department of Commerce, Bureau of Economic Analysis

a$)$ Plot the time series data and comment on the pattern you observe.

b$)$ Use weighted moving average method to forecast the demand for $2017.$

c$)$ Use exponential smoothing with optimal $\backslash (\backslash$alpha $\backslash )$ to forecast the demand for $2017.$

d$)$ Use regression method to forecast the demand for $2017-2020.$

e$)$ Compute the following measures of forecast accuracy: mean absolute error $($MAE$),$ mean squared error $($RMSE$),$ mean absolute percentage error $($MAPE$)$ for your forecasts in parts b$,$ c and d$.$

f$)$ Determine the most accurate forecast method and estimate the demand for $2017.$