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."
Explain MSE vs MAE, AUC, and imbalance handling
ML interview: losses, metrics, class imbalance, and thresholding Answer all parts concisely and precisely. 1) MAE vs. MSE in regression When would you...
Unify 7 tables and impute missing values
Using pandas, write a robust function unify_orders(...) that ingests seven dataframes (or CSVs) with possibly inconsistent column casing/whitespace an...
Design experiment with network and novelty effects
Experiment Design: New Calling Feature with Network Interference and Novelty Effects Context: You are launching a new calling feature on a large socia...
Design KYC experiment amid crypto volatility
A/B Test Design: Improve Mobile KYC Completion During High Market Volatility Context: You are analyzing a mobile onboarding funnel where the KYC (Know...
Model waiting-time abandonment via survival
Survival Modeling of Rider Abandonment During Pickup Waits Context You are modeling when a rider cancels (abandons) while waiting for pickup. Let time...
Investigate ride declines and test free trials
LA Shared Rides Down 10% MoM — Diagnostic And Action Plan Context: The Los Angeles market is seeing a 10% month-over-month decline in completed rides ...
Diagnose and reduce first-action drop-offs
Funnel Drop‑Off: Instrumentation, Incentives, Fairness, and Ownership Context You lead a program where candidates must: (1) submit paperwork, then (2)...
Design an operations dashboard with justifications
Design an Operations Dashboard for Same-Day Delivery Station Performance Goal Create a real-time dashboard for a delivery-station manager to monitor a...
Diagnose metric drop in Ads Manager
Investigate a 15% Drop in Ad-Creation Completion Rate Context On 2025-06-10, your Ads Manager dashboard shows a 15% relative decrease in the ad-creati...
Causally measure traffic reduction effectiveness
Causal Impact of Traffic Throttling on Flagged Sellers Context A traffic throttling policy was launched for sellers flagged as risky. Because the roll...
Decide launch of downranking suspected bad sellers
Experiment Design: Downranking Suspected Bad Sellers in Search Context - You are designing a decision framework and online experiment to test penalizi...
Design a Cold-Start-Aware Recommender
System Design: Two-Stage Recommender for a New Content App Context You are designing recommendations for a new content app with sparse interactions an...
Implement blocked time-series cross-validation
Implement a panel-aware blocked time-series cross-validation splitter with an embargo. Input: DataFrame columns [loan_id, msa, month]. Requirements: (...
Diagnose sales correlations without claiming causality
Correlation-Focused Analysis: Outreach Channels vs. Deal Win Rate You support a sales team and are asked to find which outreach channels correlate wit...
Identify latent group-call demand from behavior
Infer Demand for a Group Call Feature (Beyond "Call Loops") Context You are given internal user-level event data from a real-time messaging and callin...
Explain switch to product analytics and company fit
Behavioral & Leadership Technical Screen (Attentive, Data Scientist) Context You are interviewing for a Data Scientist role where you are expected to ...
Write SQL to flag Venmo ATO
SQL case: You are a Decision Scientist on Venmo’s Fraud (ATO) team. Using the schema and sample data below, write a single Standard SQL query that ret...
Design and analyze an ads ranking experiment
Ads Ranking Model: Experiment and Analysis Plan Context You are evaluating a new ads ranking model expected to increase revenue but potentially harm u...
Write SQL for ads metrics and variability
Write ANSI SQL to compute daily and campaign-level metrics, including averages and standard deviations of daily CTR and CPC, using the schema and samp...
Compute multi-account activity and unread percentages in SQL
You are given two tables. Use them as the source of truth and do not assume any other data. Table: notifications +--------+------------+------------+-...