In 1980: median family income was about $18,000, and in 2000 it was about $42,000. Find the slope of the line passing through the points (1980,18000) and (2000,42000). Interpret the slope as a rate of change. If this trend continues, estimate the median family income in 2003 m = Interpret the slope as a rate of change. Choose the correct answer below. The median family income is decreasing at the rate of $1200 per year. The median family income increases by $1200 between 1980 and 2000. The median family income is increasing at the rate of $1200 per year. The median family income decreases by $1200 between 1980 and 2000. The median family income in 2003 will be $ .