Final answer:
Real income is the average income over time adjusted for inflation since the 1800s. It provides a more accurate representation of purchasing power.
Step-by-step explanation:
The average income over time adjusted for inflation since the 1800s is known as Real Income. Real Income takes into account the effects of inflation and provides a more accurate representation of a person's purchasing power. Unlike nominal income, which is not adjusted for inflation, real income allows for meaningful comparisons of income levels across different time periods.