<P> For a population of size n, with a sequence of values y, i = 1 to n, that are indexed in non-decreasing order (y ≤ y), the Lorenz curve is the continuous piecewise linear function connecting the points (F, L), i = 0 to n, where F = 0, L = 0, and for i = 1 to n: </P> <Dl> <Dd> F i = i / n (\ displaystyle F_ (i) = i / n \,) </Dd> <Dd> S i = Σ j = 1 i y j (\ displaystyle S_ (i) = \ Sigma _ (j = 1) ^ (i) \; y_ (j) \,) </Dd> <Dd> L i = S i / S n (\ displaystyle L_ (i) = S_ (i) / S_ (n) \,) </Dd> </Dl> <Dd> F i = i / n (\ displaystyle F_ (i) = i / n \,) </Dd> <Dd> S i = Σ j = 1 i y j (\ displaystyle S_ (i) = \ Sigma _ (j = 1) ^ (i) \; y_ (j) \,) </Dd>

In calculating income for the lorenz curve one factor that is omitted is