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 Order Spending Patterns Across Cities Using SQL
Orders order_id | user_id | order_date | city | order_value 1 | 101 | 2023-01-03 | LA | 23.50 2 | 102 | 2023-01-04 | NY | 45.00 3 | 101 | 2023-01-10 |...
Optimize XGBoost for Predicting Marketing Outcomes
Gradient-Boosted Trees for Marketing Outcome Prediction Context You’re building a model to predict a marketing outcome (e.g., likelihood of conversion...
Implement BFS to Find Shortest Path in Graph
Scenario Social network needs to compute the shortest friend-distance between two users in an undirected graph containing millions of nodes. Question ...
Create Country-Level Spend Report Using Pandas
users +---------+---------+ | user_id | country | +---------+---------+ | 1 | US | | 2 | CA | | 3 | US | +---------+-...
Coordinate Resources and Resolve Conflicts for Project Success
Cross-Functional Leadership: Coordination, Conflict Resolution, Influence, and Bottlenecks Context You are leading a cross-functional data/ML project ...
Analyze Top Call Initiators and Active French Video Callers
calls +---------+-----------+-------------+---------------------+---------+-----------+ | call_id | caller_id | receiver_id | call_start_time | co...
Compute Effective Reads with SQL and Python Streaming
post_read_events +----------+---------+-----------+---------+--------------------+---------------------+---------------------+ | event_id | user_id | ...
Implement Reservoir Sampling; Analyze Time and Space Complexity
Scenario Process an unbounded stream of user IDs and maintain a uniform random sample of k users in memory. Question Implement reservoir sampling for ...
Analyze Oculus App Engagement with SQL Queries
AppUsage +---------+--------+-----------+--------------+------------+ | user_id | app_id | category | minutes_spent| usage_date | +---------+--------...
Analyze Video View Distribution: Mode, Median, Mean Comparison
Scenario You are analyzing user engagement on a short-video sharing product. The team needs statistical insights into how views and shares behave acro...
List Transactions During Active 'Gold' Membership Period
customer_profile +-------------+----------------+--------------------+-------------------+ | customer_id | membership_type| membership_start_date| mem...
Explain MySQL to MS SQL Server query syntax differences.
transactions | id | user_id | amount | txn_date | |----|---------|--------|----------| | 1 | 1001 | 25.00 | 2023-07-01 | | 2 | 1002 | 40.00 ...
Compare Instagram and Facebook Stories Using Key Performance Metrics
Scenario You are a data scientist tasked with quantitatively comparing the success of Instagram Stories versus Facebook Stories. Question 1. Define wh...
Predict Next-Period Conversion Rate Using Historical Campaign Data
Predicting Next-Period Conversion Rate from Campaign Logs Context You have historical campaign panel data with columns: adid, date, impressions, click...
Explain Resolving a Complex Technical Challenge Successfully
Behavioral: Complex Technical Problem You Solved (Data Scientist – Onsite) Prompt Describe a complex technical problem you personally resolved. Includ...
Prove high-quality pixels improve ad performance
Context You support an ads platform where each advertiser has a pixel. Pixel quality varies due to missing/invalid signals, which can affect attributi...
Compute probability in urn with green returns
Urn Sampling with Replacement for Greens Only You have an urn with colored balls. You repeatedly draw one ball uniformly at random: - If the ball is g...
Assess card transactions and plan risk strategy
Card Fraud Decisions and Cold‑Start Risk Strategy Context You are designing the first version of card risk controls for an online checkout platform. Y...
Model Shot Success by Location
You need to build a model that predicts the probability that a shot becomes a goal for every location on a soccer field. Assume you have historical sh...
Design Excel visuals for risk results
Excel Dashboard Design: Communicating EL, RWA, and Concentration Risk Context You are preparing an Excel dashboard for a credit portfolio review that ...