Final answer:
A line graph is the best choice for displaying changes in the federal hourly minimum wage over time from 1990 to 2007, as it clearly illustrates trends and fluctuations in the wage rates.
Step-by-step explanation:
To best show the changes in federal hourly minimum wage from 1990 to 2007, a line graph would be most appropriate. This type of graph is ideal for displaying data over time and allows for easy visualization of increases or decreases in the minimum wage throughout the years. Each year would be represented as a point on the graph, and the points would be connected by a line that illustrates the trend of changes in the minimum wage, making it straightforward to observe the rate at which the minimum wage has changed during the specific time period.