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."
Compare trees, RF, and gradient boosting
Decision Trees, Random Forests, and Gradient-Boosted Trees You are interviewing for a Data Scientist role and are asked to compare common tree-based m...
Compare LLN and CLT with heavy tails
Explain the Law of Large Numbers vs the Central Limit Theorem, including their assumptions and convergence guarantees. Construct a concrete counterexa...
Design B2C chatbot success metrics and test plan
You own 'euro-chat', a B2C customer-support chatbot that aims to deflect agent contacts while preserving customer satisfaction. Design a rigorous succ...
Handle conflict and time-pressured decision
Describe a time you had to make a high-stakes recommendation under time pressure when key stakeholders disagreed (e.g., ops wants to ramp a change tha...
Compute rolling cold-delivery rates with windows
Assume a food-delivery platform with the following schema. Use PostgreSQL. A delivery is considered "cold" if food_temp_c < 40 at dropoff OR there is ...
Design end-to-end regression for energy demand
End-to-End Daily Energy Prediction for Commercial Buildings Context You are asked to design and justify an end-to-end regression system that predicts ...
Demonstrate leadership under strict rules
Behavioral — STAR: Operating Under a Non‑Negotiable Policy Context: Onsite behavioral & leadership interview for a Data Scientist. Describe a specific...
Write and explain gradient descent pseudocode
Task: Batch Gradient Descent for Linear Regression (with Intercept) You are interviewing for a Data Scientist role and are asked to implement batch gr...
Persuade engineers to launch pinned-unread chats
Pitch: Pinning Conversations for High-Unread Users Context You are proposing a feature that pins a small set of conversations to the top of the inbox ...
Compute unread and multi-account user percentages
You’re given two tables. Write ANSI-SQL to answer parts (a)–(d). Treat a notification as unread if read_at IS NULL. Denominator for user-level percent...
Compare two stores’ profits rigorously
Prompt: 14-Day Plan to Decide Which Snack Shop Will Be More Profitable Next Quarter Context: Two snack shops operate simultaneously at a school gate. ...
Compute monthly CRR with merges and gaps
You are given PostgreSQL tables user_profile(user_id, signup_ts, country, is_employee, is_test), user_events(user_id, event_ts, event_type, revenue, p...
Diagnose and optimize shared workspace marketplace conversion
You manage a two-sided marketplace for shared workspaces. Daily sessions are ~200,000. Booking conversion fell from 3.2% (2025-08-01 to 2025-08-14) to...
Describe accomplishment, failure, and helping others
Provide three distinct examples from the last 24 months: (1) Your most consequential accomplishment—context, specific goal, constraints, your actions,...
Compare list/dict; parse JSON/CSV at scale
Compare Python list and dict precisely: for append/insert/lookup/update/delete, state average and worst-case time complexity, memory implications, and...
Explain a project with measurable impact
Choose one impactful project from your resume and deep-dive it in 8–10 minutes: define the problem and business goal, baseline and target, your precis...
Design ML deployment with GitHub and Jenkins
Design an end‑to‑end ML deployment for a prediction model using GitHub and Jenkins: 1) Propose a repo layout (src/, features/, data_contracts/, tests/...
Design an experiment for delay drivers
Estimating the Causal Effect of Reducing Gate Turnaround on Flight Delays Context: Operational drivers of flight delays (e.g., gate turnaround, taxi-o...
Model schema and query new-market readiness
Assume today is 2025-09-01. You are given (or can propose) a minimal schema to assess new-market readiness and early performance. Use the schema below...
Explain motivation and align expectations for L4 role
Behavioral Prompt: L4 IC Data Scientist — Motivation, Plan, and Expectations Context You are interviewing onsite in a Behavioral & Leadership round fo...