Update inequality.md

Author: orectique

lectures/inequality.md

@@ -337,7 +337,7 @@ plt.show()
 Let's examine the Gini coefficient in some simulations.
 
 The following code computes the Gini coefficients for five different
-population.
+populations.
 
 Each of these populations is generated by drawing from a 
 lognormal distribution with parameters $\mu$ and $\sigma$.