The report analyzes monthly passenger movement data between January 1990 and April 2004. Data on three monthly time series are given in the file Sept 11 Travel.xls for this period: (1) actual airline revenue passenger miles (Air), (2) rail passenger miles (Rail), and (3) vehicle miles traveled (Auto). In order to assess the impact of September following approach: Using data before September 11, BTS took the 11, it fore- casted future data (under the assumption of no terrorist attack). Then, BTS compared the forecasted series with the actual data to assess the impact of the event. 1. Is the goal of this study descriptive or predictive? 2. What is the forecast horizon to consider in this task? Are next-month forecasts sufficient? 3. What level of automation does this forecasting task require? Consider the four questions related to automation. 4. What is the meaning of t = 1, 2, 3 in the Air series? Which time period does t = 1 refer to? 5. What are the values for y. y2, and y3 in the Air series?