The overall demand for finished goods and services in an economy at a certain period is known as aggregate demand (AD) or domestic final demand (DFD) in the field of macroeconomics. Effective demand is a common name for it, however other times this term is used to make a distinction. This is a country's demand for its gross domestic output. It details the volume of goods and services that will be bought at every price point. The aggregate demand is made up of investment, corporate and governmental expenditures, consumer spending, and net exports. Real output is represented on the horizontal axis and the price level is plotted on the vertical axis to represent the aggregate demand curve. Although it is presumed to be downward sloping, the Sonnenschein-Mantel-Debreu findings demonstrate that the curve's slope
I'd say, since he admit to putting so much time and effort into psychology, there's simply no need to drop the course. So therefore, your friend is incorrectly reasoning.
Purchasing power is related to real income and not to nominal income. Even though workers had a $10 increase in their average nominal income, due to the effects of inflation, that increase does not necessarily reflect an improve in purchasing power.
