This Wolfram Alpha Widget:
http://www.wolframalpha.com/widgets/...2fb3bb85e071b4 should calculate it if I put in all the equations properly (I'm not sure if I completely understand how the district ranking works, so there may be errors). It doesn't require any other programs to run (I know some students who don't have Excel so I decided not to try and figure out the equations in it). Please let me know if you catch any problems in it and I'll try to fix them.