Lorenz curve = () is used to represent a wealth distribution in a nation. The entire population is plotted along the x-axis from poorest to richest, and the height of the curve on the y-axis shows the percentage of total income received by the proportion of the population given on the x-axis. Graph of function = , called the line of perfect equality, represents the population where everyone has the same income. The area between the graphs of the two functions for 0 100 shows the country's income inequality.

The table below gives the percentage of income for selected percentages of people in a country.

	10	20	30	40	50	60	70	80	90
	3.32	6.41	8.96	12.39	19.32	28.11	38.65	55.13	78.29

1. Use Excel to fit a quadratic curve to the given data.
2. Plot the data along with the obtained curve above and the line = .
3. Using the obtained curve, approximate the income inequality for the given country.