[mathking]

I think that one thing you definitely need to look at in addition to what you have done so far (which seems sound) is to look at how likely veteran teams are to place in the top 8 compared to younger teams. Which is different from the analysis you have done so far. It is an interesting question though. Gives me a good idea for an assignment for AP Statistics class while I am gone for the regional this weeked.

OK, I also just took a look at some of the data and it occurs to me that your result is exactly what FIRST would be trying to achieve by randomizing matches as it did.