Consider the monthly U.S. unemployment rate from January 1951 to February 2004 in the file m-unemhelp.txt. The data are seasonally adjusted and obtained from the Federal Reserve Bank in St. Louis.
Build a time series model for the series and use the model to forecast the unemployment rate for March, April, and May of 2004. In addition, compute the average period of business cycles if they exist.
(Note that more than one model fit the data well. You only need an adequate model.)