Want to know more? Check out these sites:

http://www.umich.edu/~snre492/statter.html
http://www.uncwil.edu/riverrun/river_tutorial/CFRSystem.htm
http://www.scribd.com/doc/36760266/Factory-Farmed-Hogs-in-North-Carolina

http://www.unc.edu/courses/2009fall/econ/051/001/SOT_Lagoons/Hosterman_enviro.pdf

http://www.epi.state.nc.us/epi/mera/iloodoreffects.html

http://www.grist.org/article/north-carolina-governor-asked-to-address-hog-industrys-health-impacts/