A graph showing the changes in car prices over time is a descriptive graph.

A graph showing the supply and demand functions for automobiles is an analytical graph. We can use it to analyze how changes in price, income, and tastes will affect car sales.

Many of the statistics used by economists are estimates or numbers based on estimates.

The average income of U.S. families.
The selling price of homes in Des Moines.
The population census for Ames.