Which curve is used to demonstrate shifts in income distribution among a population over time?

The Lorenz curve is the correct choice for demonstrating shifts in income distribution among a population over time. This curve provides a graphical representation of income inequality by showing the proportion of total income earned by cumulative segments of the population. When plotted, it allows for a comparison between actual income distribution and perfect equality (where everyone has the same income), which is represented by a 45-degree line.

As income distribution shifts—whether it becomes more equal or more unequal—the Lorenz curve changes shape. If income becomes more concentrated among the wealthiest individuals, the curve bows further away from the line of equality. Conversely, if income distribution becomes more equal, the curve moves closer to the line.

The Gini curve, often confused with the Lorenz curve, uses the information derived from the Lorenz curve to produce a numerical measure of income inequality known as the Gini coefficient. While both are concerned with income distribution, the Gini curve does not directly illustrate shifts over time in the same graphic manner as the Lorenz curve does.

The supply curve and the Phillips curve are unrelated to income distribution. The supply curve represents the relationship between quantity supplied and price in markets, while the Phillips curve illustrates the inverse relationship between inflation and unemployment in an economy. These concepts do