Robinhood Data Scientist Interview Experience — Sample-Size Math in the Experimentation Round

Robinhood·Data Scientist·Oct 2025
OnsiteRejectedeasy

I've been getting rejected a lot in interviews lately. Today I got another rejection — they said my performance in the experimentation round wasn't good. I felt like I did really well in that round; I covered all the concepts I'd prepared ahead of time. I honestly don't see what was bad about it.

For the experimentation round, they asked about the benefits of launching fractional shares and how to prove those benefits. Then they asked how to calculate sample size, how to adjust the sample size if it needs adjusting, and what to do if the sample size you'd need is larger than the amount of data you actually have.

The other rounds were all standard virtual onsite interviews. Looking back at the whole loop, I think coding was my weakest round — I didn't finish in time, even though I knew how to solve everything, I just ran out of time. The recruiter told me I'd passed the technical bar, so I'm guessing that came from the interviewer's assessment of me — thanks to her for that.

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Curated and edited by PracHub

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Interview at a glance

Company
Robinhood
Role
Data Scientist
Rounds
Onsite
Outcome
Rejected
Difficulty
easy
Interview date
Oct 2025
Questions from this interview
1 question

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