A time-series plot often helps you determine the appropriate model to use. For this problem, use each of the time series presented in the following table and stored in TsModel2:
a. Plot the observed data (Y) over time (X) and plot the logarithm of the observed data (log Y) over time (X) to determine whether a linear trend model or an exponential trend model is more appropriate.
b. Compute the appropriate forecasting equation.
c. Forecast the value for 2012.