The Board of Governors of the Federal Reserve publishes the 1-quarter-ahead forecasts of real GDP growth. These are known as the Greenbook forecasts. Download the realized values of GDP growth (from the website of the Federal Reserve Bank of Philadelphia, www.phil.frb.org/econ/forecast) and compare with the Fed forecasts. Compute the 1-quarter-ahead forecast errors. Plot the time series of realized values, forecasts, and forecast errors. What do you observe in these time series? Compute the descriptive statistics of the three series. Compute the ACF and PACF of the realized values, forecasts, and forecast errors. Do you observe time dependence?