I was notified 2 weeks ago. I got accepted 2 days after my interview (which was 2 weeks ago so). I declined the offer.
The deadline isn't may as I've read on this post, it's may for online students only.
The interview is pretty short. I was interviewed by the "R boss". He did not asked me any questions about linear algebra or proba as my background is more than enough. He did ask me question about programing though. If you know a bit of R, it's a good point; a question he asked me: does R work with a generating function? (or something like that).
If you ever get an interview, I suggest you convince him you like programing.