Data Scientist Interview Questions
Practice 2,964 real Data Scientist interview questions for 2026. Data Scientist interview questions drawn from Meta, Capital One, Amazon, Google, TikTok and similar employers — real questions from actual interviews with detailed solutions — designed to accelerate your interview preparation for product analytics, ML and production data roles. This collection emphasizes the practical skills interviewers test: SQL and data manipulation, experiment design and A/B testing, statistical reasoning, Python coding for data problems, model evaluation and feature engineering, plus machine-learning system tradeoffs and metric design. What’s distinctive about modern data-science loops is the blend of product thinking and reproducible ML: expect hands-on SQL tasks and funnel analysis in screens, deeper experiment-design and causality questions in mid rounds, and coding or modeling challenges plus ML-system discussions in senior loops. Interviewers evaluate problem framing, statistical rigor, and how you communicate decisions to product partners. To prepare, prioritize daily SQL practice (CTEs, window functions), refresh hypothesis-testing and power calculations, rehearse concise metric-driven narratives, and build a few end-to-end model or experiment stories you can explain clearly under time pressure.
"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"
"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"
"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."
"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."
"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."
"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."
"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."
"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."
"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."
"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."
"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Sketch distributions and compare mean/median/mode
Sketching distributions and comparing mean, median, and mode This is a conceptual statistics question with two independent scenarios. For each, you sk...
How would you use propensity score matching here
You want to estimate the causal effect of a new recommender feature on 7-day retention. The feature was not randomized: users “opt in” after seeing a ...
Apply Bayes' rule to compute posterior
A binary event \(A\) (e.g., “user is a payer” or “patient has a disease”) has prior probability \(P(A)\). You observe evidence \(B\) (e.g., a model pr...
Assess Fundamental Statistics Knowledge in Data-Science Interviews
Fundamental Statistics (Technical Phone Screen) Context You are given standard statistics tasks commonly used in a data-science interview. Assume all ...
Implement monotonic-array linear interpolation
Question Implement a function interpolate(array_x, array_y, x) that returns the linearly interpolated y-value for a query x-value, given paired data p...
Fit logistic regression and return top features
You are given: - X: a 2D numeric array where each row is a feature and each column is an observation (shape: n_features x n_samples). - feature_names:...
Assess Stripe Capital Strategy
Stripe is evaluating a merchant-financing product called Capital for existing merchants. Merchants are pre-qualified using Stripe's internal data. App...
Analyze distribution of a 3-dice product
You roll three independent fair 10-sided dice. Each die shows an integer in \(\{0,1,\dots,9\}\) with equal probability. Let the outcomes be \(X,Y,Z\),...
Measure feature impact with switchback, PSM, and CACE
You work at a ridesharing company and want to measure the impact of a new membership feature on rides-per-user (RPU). Across the parts below you will ...
Design A/B test for AI chat box
Context A social platform (e.g., Reddit) plans to launch an AI chat box that answers user questions. The functionality overlaps with the existing Sear...
Implement Stratified Sampling by Country
You are given a large in-memory Python list named records, where each element is a dictionary with at least the following keys: - country: str - devic...
How would you evaluate UberEats growth?
You have just joined UberEats as a senior data scientist. The interviewer asks you to reason about marketplace health and causal impact. Answer the fo...
Compute bus-on-time and dice-sum probabilities
You are asked two basic probability questions. A) Catching a bus to arrive before a movie A person is going to the cinema. The movie starts in L minut...
Explain Train-Test Performance Gap
A supervised model for a TikTok-like product problem performs very well on the training set but much worse on a held-out test set. How would you diagn...
Relate coefficients under linear feature transformation
Suppose you are fitting a linear regression model and you consider two different feature parameterizations. Original features: x1, x2. Transformed fea...
Compute gala vs online break-even donors
A nonprofit must choose one of two fundraising options. Option A (Gala): capacity 100 attendees; fixed cost $20,000; variable cost $100 per attendee. ...
Find top category per region in Aug 2025
You are given the following schema and sample data. Schema: - customers(customer_id INT, name TEXT, region TEXT) - orders(order_id INT, customer_id IN...
Design robust experiment for ambiguous core change
You must evaluate a core product change that likely has network effects (e.g., a matchmaking tweak in a large online game with 8M DAU). Define the pri...
Describe resolving a high-stakes research disagreement
Describe a time you and a stakeholder strongly disagreed on the framing or interpretation of a technical problem (e.g., a probability/statistics assum...
Aggregate D1 retention cohorts in SQL
Today is 2025-09-01. Using SQL (optionally outline a pandas approach too), compute daily engagement and D1 retention for the last 7 days (2025-08-26 t...