I did not have to interview for this position. I was hired for this role because I was asked to do it for a professor whose class I took in the year prior to the job offer.

Direct interview with professors. They asked me about my background, previous research experience, programming skills, grades and the content of some advanced graduate courses, and the familiarity with topics they were working on. Because my research experience is not very matched with their fields, I was asked to complete another technical exercise in the following days.