Table 1 gives the amount of federal spending in billions of dollars for national defense for several years. Use the regression equation to find how fast the spending was growing in 2003.
 Explain why someone might be hesitant to make predictions about the rate of change of national defense spending, based on this equation.

Table 1. Year 1990 1995 1999 2000 2001 2002 2003 National Defense Spending National Defense Spending ($ billions) 299.3 272.1 274.9 294.5 305.5 348.6 404.9 Source: U.S. Census Bureau, Statistical Abstract of the United States, 2004-2005.