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."
Design a robust pro-ranking A/B test
Experiment Design: Evaluating a New Pro Ranking Algorithm (Ranker) in a Two‑Sided Marketplace You are designing an experiment to evaluate a new pro ra...
Measure notification impact and set guardrails
New Notification Type: Measurement Strategy (Beyond Vanity Metrics) You are launching a new in-app/push notification type aimed at increasing user eng...
Test regional response-rate differences rigorously
Goal Assess whether provider response rates differ by region after adjusting for job category mix and time. Data You have job-level observations with ...
Navigate urgency, priorities, and conflict
Behavioral & Leadership: Ambiguity, Dependencies, and Execution Under Pressure You will describe one real project where you faced high ambiguity and c...
Design an A/B test; choose Z vs T
A/B Test on a Signup Funnel: Sample Size, Test Choice, Sequential Design, and Causal Plan Context You are planning a two-variant A/B test on a signup ...
Predict job changes month by month
Predict Monthly Job-Change Risk (Discrete-Time Survival Setup) Context You are building a monthly model to predict the probability that a LinkedIn mem...
Design a hybrid marketplace fraud system
Design a Fraud Detection System for a Marketplace and Profile Credentials Context You are a data scientist at a two‑sided marketplace where users can ...
Design an A/B test for a Celebrate reaction
Experiment Design: Adding a "Celebrate" Reaction to WeChat Moments Context WeChat Moments is a friend-based social feed with posting, viewing, and rea...
Design causal study for reminder impact
Observational Causal Study: Reminder Program With Staggered Market × Channel Launch Context You are evaluating the causal impact of medication-subscri...
Compute maximum concurrent trips from intervals
You’re given n trip intervals [start, end) in seconds, where start < end, representing when a rider’s trip starts and ends in a city on a specific day...
Implement sliding-window device anomaly
Streaming detection algorithm: Implement a function process_logins(stream) that consumes a time-ordered stream of login events (user_id, ts, device_id...
Estimate and validate weights for engagement actions
Goal Design a principled weighting scheme for impression-level actions to construct a socialness score S = w_like · Likes + w_comment · Comments + w_s...
Compute GSP vs VCG payments with reserves
Sponsored Search Auction with Quality Scores and Reserve You are analyzing a single-query auction with 2 ad slots. Position CTR multipliers are [0.10,...
Evaluate friend-interaction feature with network interference
Experiment Design: Network-Aware Test for a "Friend Interaction Boost" in Feed Ranking Context You plan to ship a ranking change that boosts items in ...
Design an A/B test for pre-roll ads
A/B Test: Reduce Mobile Live‑Stream Pre‑Roll Ad Frequency by 20% Context: You are designing an experiment on mobile live streams to evaluate reducing ...
Maintain target margin with fixed costs
Target Profit Margin With a Mixed-Product Portfolio Context You sell two burger products (classic and vegan) at the same price but with different unit...
Compare average unit profit under mix shift
Profit Comparison Across Menu Scenarios Context A quick-service restaurant is evaluating average profit per burger under two menu strategies. Assumpti...
Lead an ML project under ambiguity
Behavioral and Leadership: End-to-End ML Project Context: Onsite Data Scientist interview. Use one concrete project you personally led end-to-end. Be ...
Plan and validate ranking experiment
Evaluate a New Home-Page Ranking Algorithm: 3-Stage Plan Context You are introducing a new ranking algorithm for the home page. You must validate it s...
Design a fintech product ranking system
Build a Personalized Ranking System for Financial Products (App Home Page) Context You are the first Data Scientist partnering with a PM to build an e...