I have applied three or four different universities for graduate study in statistics last fall and this spring but All of them rejected my application. I have MS in math and have good GPA but my GRE analytical score is low. Does any body know any school which is easy to get in with assistantship in statistics? University of Missouri columbia waitlisted my application for spring but I have not heard any thing yet. Any positive suggestion will be appreciated.

the first mistake you make was that you only applied to only 3-4 universities. you should have applied to 8-10 universities with few universities that you can easily get accepted just to hedge the risk of not getting accepted into a good school that you wanted to go. anyway, it's too late to talk about that now. my best suggestion is to talk to your adviser or dean of the university where you graduated to see if you can get admission there. give GRE test again and transfer to different university of your choice.
or wait and give GRE one more time and apply for fall.
again, i am giving you this suggestion based on the assumption that you were rejected because of low GRE score.

and sorry, i have no idea about assistantship in statistics.

anyway, good luck

Try,
Illinois State University.
I have heard, probability of getting assistanceship there is high.

Dude  try University of calgary and university of alberta in canada. They have very good scholarship for PhD students. you will get at least 2000 dollars every month.Once you have PhD from those top universities, you can easily come back to US and find job.