Upstart Intern Data Scientist Interview Experience — Same Questions Recycled Between Rounds

Overall, the experience was pretty good. The HR person and the few interviewers I dealt with were all really supportive — nobody looked down on international candidates.

There was no HR screen — I went straight into the first-round tech interview. The interviewer didn't even ask about my resume; we did a quick self-introduction and then went straight into the questions. The questions were:

1. An atom has a half-life of 1 day. What's the probability that, out of 100 atoms, some number are still alive after 10 days? Write a simulation — input is number of days m and number of particles n, output the particle states.
2. A classic Bayes' formula question, very simple — just plug the given conditions into the formula.
3. Implement a factorial function in Python, then figure out how many ways there are to compute the number of trailing zeros.

A little less than a week later, HR called directly to tell me I'd made it to the final round, and said the invite was still being processed and I'd get a scheduling link in a few days. In reality it took over a week after that call before I actually got the schedule — at one point I genuinely thought I'd been ghosted. The final round was two back-to-back virtual onsite interviews: one on prob & stats, one on stats & ML. One of them had about half an hour of resume discussion built in; the other went straight into questions. The questions were:

1. y = x + e, where x, e ~ N(0,1) and independent. Do OLS regression of y on x and of x on y, and find the coefficients.
2. The classic Monty Hall problem.
3. An n-sided die — what's the expected number of rolls before you've seen every face?
4. Difference between L1 and L2, and the difference between ridge and lasso.
5. A LeetCode-style coding question (the original post spelled this one out in coded phonetics — likely to dodge forum filters — so the exact problem isn't clear from the text).

Weirdly enough, I think the interviewers didn't coordinate well — two of the questions in the final round were actually repeats from the first round. I suspect they have a question bank and just pull from it each time. That said, these questions were honestly really easy compared to quant interviews... The day after the final round I got an HR call saying I'd passed, and I got the offer a week later. Communication throughout was smooth.