Questioning the GDP Deflator: Measuring Average Price Output?

[jackylaucf]

I would like to raise a question about GDP deflator. In my macroeconomics textbook, there is a statement like this: "GDP deflator gives the average price of output". I wonder why the deflator will give the average price as it only measure the ratio between nominal GDP and real GDP...
Thanks for help!

 

[Tosh5457]

I would like to raise a question about GDP deflator. In my macroeconomics textbook, there is a statement like this: "GDP deflator gives the average price of output". I wonder why the deflator will give the average price as it only measure the ratio between nominal GDP and real GDP...
Thanks for help!

That's not the definition of deflator, the definition is the Prices_year_n*Quantities_year_(n-1)/(Prices_year_(n-1)*Quantities_year_(n-1) thus giving the ratio between prices of an year n and the prices of the year n-1.