In: Economics
1. Quadratic Lorenz Curve. Suppose the cumulative income distribution is given by x^2 , where 0 ≤ x ≤ 1, that represents the Lorenz curve of an economy. What is the Gini coefficient? Graph your results. For your information, the area under the Lorenz curve x^2 from 0 to 1 is 1/3 .
Gini coefficient would be the ratio of area between Lorenz curve
and 45 degree equality line to the total area under the 45 degree
equality line. We can calculate it as
or
or
or
or
or
or
.
With the info you have provided, we can calculate it as
, where A is the area between the Lorenz curve and equality line
and B is the area below the Lorenz curve. But, A+B is the area
below the equality line, which is 0.5. Hence, we have, A=0.5-B, and
for B=1/3, we have A=0.5/3. Hence, the Gini coefficient would be
.
The graph is as below.