Although you should not expect a perfectly fitting model for any time-series data, you can consider the

Question:

Although you should not expect a perfectly fitting model for any time-series data, you can consider the first differences, second differences, and percentage differences for a given series as guides in choosing an appropriate model.

For this problem, use each of the time series presented in the table above and stored in Tsmodel1 :
a. Determine the most appropriate model.
b. Compute the forecasting equation.
c. Forecast the value for 2015.