collect suggestions on choosing graduate school

I have got three offers from the following universities which are different in several aspects.
would you like to give me some suggestions on them.
Thank you very much.

1 univerisity of connecticut, anthropology, teaching assistantship $12,915

2 univerisy of kansas, population dynamics and evolutionary genetics, Research assistantship $15000+possible5000

3 university of binghamton-SUNY, evolutionary biology and evolutinary anthropology, $9,600 + possible 2500,