I applied online and received an email the next day about setting up a phone interview. The first one was mostly mental math and was average. They contacted me after about a week to set up a second interview, which had more probability and expected value questions that required more thought. After about a week or so, they contacted me again for a third interview, which lasted about an hour and was a really interesting question that was more related to their work. The interviewers were all really nice.
Interview questions [1]
Question 1
The questions all tested your critical thinking abilities, and the most difficult one was probably the 3rd interview.
They tend to examine the logical thinkers that can communicate clearly and concisely, and some problem-solving exercises intended to explore how you gather and apply new information, very different from other tech companies' interviews.
Initial application and online assessment. Had a first round behavioral interview where they asked me about myself, my experiences, and a couple of brain teasers. The interviewer was very nice.
Phone interviews (at least 3) - questions were of mixed difficulty (some pretty hard) but the interviewers were friendly and they gave helpful hints. Kind of fun - review probability and game-type questions.