Final answer:
An index is a statistical measure of price movements. Economists use index numbers to measure the price level rather than the dollar value of goods because they provide a comparative basis for analysis and allow for easier tracking of inflation.
Step-by-step explanation:
An index is a statistical measure of price movements. In the context of economics, an index number is a unit-free number derived from the price level over a number of years. It makes computing inflation rates easier because the index number has values around 100. Economists use index numbers to measure the price level rather than the dollar value of goods because the index number provides a comparative basis for analysis and allows for easier tracking of inflation.