These data are from the 2000 U.S. census. This file contains the median family income in 1999(dollars) by family size.
I collected them from the website of U.S. Census Bureau.
I want to look at if there is some relationship between the income and the size of family. 
For every given size of family, I chose the data for 7 states, namely Arizona,California,Colorado,Florida,Georgia,Illinois and Indiana.

Variables names:
fsize: number of persons in a family
income: the median family income