A data scientist is generally a though leadership level position. Assuming you’ve done your due diligence, you shouldn’t be wasting interview time with hypotheticals. Pick a data science problem that you’ve already solved, describe it in general terms, and ask the candidate how they would solve it. Have a discussion about the types of challenges you are facing and see what s/he has to say in response.
Remember when dealing with leadership level positions, the candidate is interviewing you just as much as you are interviewing them.