Editing Gini coefficient (section)

=== Example: Two levels of income ===
The extreme cases are represented by the most equal possible society in which every person receives the same income ({{nowrap|''G'' {{=}} 0}}), and the most unequal society (with ''N'' individuals) where a single person receives 100% of the total income and the remaining {{nowrap|''N'' − 1}} people receive none ({{nowrap|''G'' {{=}} 1 − 1/''N''}}).

A simple case assumes just two levels of income, low and high. If the high income group is a proportion ''u'' of the population and earns a proportion ''f'' of all income, then the Gini coefficient is {{nowrap|''f'' − ''u''}}. A more graded distribution with these same values ''u'' and ''f'' will always have a higher Gini coefficient than {{nowrap|''f'' − ''u''}}.

For example, if the wealthiest ''u ='' 20% of the population has ''f ='' 80% of all income (see [[Pareto principle]]), the income Gini coefficient is at least 60%. In another example,<ref>{{cite news |last1=Treanor |first1=Jill |date=2015-10-13 |title=Half of world's wealth now in hands of 1% of population |newspaper=The Guardian |url=https://www.theguardian.com/money/2015/oct/13/half-world-wealth-in-hands-population-inequality-report}}</ref> if ''u ='' 1% of the world's population owns  ''f ='' 50% of all wealth, the wealth Gini coefficient is at least 49%.