There were just two phone interviews. The first interview was a mix of code test, behavior and statistical questions. The code test was super easy as long as you were proficient in summarizing data and doing basic statistical analysis, such as aggregation, estimating missing values and linear regression. The second one was much harder and no question was necessarily related with my resume. I felt it was conducted by a senior BIE or data scientist. They hoped you could consider the problem more thoroughly and in a creative way. Of course, they also asked statistical questions, but I feel that was the easiest part.