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."
Analyze HT vs HH stopping-time probabilities
Coin-Flip Stopping Game: HT vs HH You repeatedly flip a coin until either the pattern HT appears (Player A wins) or the pattern HH appears (Player B w...
Resolve conflict with measurable outcome
Behavioral: Conflict With a Teammate or Stakeholder (Data Scientist — Technical Screen) Provide a specific, first-person example. Use a clear structur...
Solve two-pointer, sliding-window, and string tasks
Solve the following three coding tasks: 1) Two-pointer in-place de-duplication: Given a non-decreasing integer array nums and an integer k >= 1, modif...
Write SQL to quantify outage revenue loss
A database outage blocked premium membership registrations from 2025-01-01 to 2025-03-31 (inclusive). Members intend to start on intended_start_date, ...
Evaluate payback and sensitivity for solar vs ethanol pilots
Renewable Pilot Evaluation — Payback and Sensitivity Context Two 1-year-operated pilot plants are being considered to add renewable capacity. Assume s...
Sketch function from derivatives and limits
Function analysis with derivative and concavity constraints Context (clarified): Assume f: R → R is differentiable everywhere and twice differentiable...
Demonstrate advanced techniques and ethical judgment
Behavioral & Leadership — Data Scientist Technical Screen Provide concise STAR responses (4–7 sentences each) with quantifiable outcomes. Focus on you...
Derive expected meetings given nonempty room
Zero-Truncated Binomial: Random Room Assignment Setup - There are N rooms labeled 1, 2, ..., N. - K meetings are scheduled; each meeting independently...
Compare two ad insertion strategies
Ad Insertion Strategies for a 100-Post Feed You are evaluating two ad-insertion strategies on a feed with 100 posts: - Strategy A (Stochastic): Indepe...
Impute, join, and upsert using SQL and Python
Write both SQL and Python (pandas) to complete the following data-manipulation tasks. Assume today is 2025-09-01 for any time filters. Schema: custome...
Compute and correct correlation significance inflation
Sales Outreach Correlation Analysis: Inference, Multiple Testing, Power, and Simpson’s Paradox Context You are analyzing sales data to understand rela...
Lead alignment under ambiguity and pressure
Behavioral/Leadership Case: Resolving KPI Misalignment Under Time Pressure Context You are a data scientist preparing for an onsite interview. Multipl...
Design a production face recognition system
Design an On-Device Face Recognition System for Mobile Access Control Context You are designing a face-based access control system for mobile devices ...
Write SQL/Python for CTR analytics
Part A — SQL (use the schema and sample data below): Compute 48-hour unique CTR for campaign_id=100 by variant, deduplicating to the earliest send per...
Design streaming new-vs-returning monthly metrics
Streaming design: Monthly NEW vs RETURNING request shares (event-time, with late/out-of-order and duplicates) Context You receive a high-volume event ...
Define success metrics for Instant Book
Instant Book: Metrics, Measurement, Rollout, and Risk Plan Context You are evaluating an "Instant Book" feature that allows customers to immediately b...
Derive no-click probability and sketch implications
Click Probability Across Repeated Impressions Context: We show A impressions of the same item to a user. Unless otherwise stated, each impression is a...
Compute shop visibility and intent metrics in SQL
Schema (PostgreSQL). Tables: users(user_id) shops(shop_id, shop_name, merchant_type) posts(post_id, shop_id, is_shoppable BOOLEAN, created_at TIMESTAM...
Write SQL and pandas for shopping events
Use the schema and sample data below to answer SQL and pandas tasks. Treat 'today' as 2025-09-01. Schema users(user_id INT, country STRING) pins(pin_i...
Estimate Super Bowl QR ad sign-ups
Incremental Sign-ups From a Super Bowl QR Ad (48h) CoinFactory ran a 60-second Super Bowl TV spot on 2025-02-09 with a QR code to a signup page. Succe...