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."
Query seven-day conversion with windows and dedupe
Assume all timestamps are UTC. Treat "today" as 2025-09-01. Define "last 7 days" as the inclusive window [2025-08-26 00:00:00, 2025-09-01 23:59:59]. S...
Test 15s to 60s video length change
Experiment Design: Change Default Creator Video Length from 15s to 60s Context You are designing an A/B test for a short‑form video platform with two ...
Cover HR screen: role, motivation, comp, immigration, location
Prompt: 90‑Second Summary and Logistics for a Data Scientist Technical Screen Context You are preparing for a Data Scientist technical screen. Provide...
Evaluate concession gift-card policy with DID
Evaluate a Gift-Card Concession Pilot (Causal Impact with Staggered Adoption) Context Several regions piloted a policy: when a shipment is lost or dam...
Diagnose a watch-time drop and design experiments
Evaluate a New Preloading Strategy for a Short‑Video App (New Users) Context On 2025‑08‑20, a new preloading strategy was rolled out to 30% of traffic...
Design metrics and write SQL for a case
Case: Measure the impact of outreach on subsequent purchases and diagnose anomalies. Define your primary metric and write SQL. Schema and tiny samples...
Implement streaming per-user reservoir sampling
Design and code (in Python) a streaming algorithm that ingests an unbounded event stream of tuples (user_id, event_time, event_type) and maintains, fo...
Write SQL for snapshot features and labels
Use 'today' = 2025-09-01. Invented schema (UTC): users(u_id INT, signup_dt DATE, country STRING) events(u_id INT, event_time TIMESTAMP, arrival_time T...
Implement fast sampling for weighted k-sided die
You must sample from a categorical distribution over k outcomes with probabilities p1..pk (sum to 1) without using built-in categorical samplers. You ...
Design a small-sample launch experiment in Europe
Launch Test Design: Early-Access EU Businesses Context You have an early-access pool of 1,200 EU businesses for a new chat subscription offering. Chat...
Justify EU B2B Chat Product Strategy
Executive Brief Task: EU B2C Customer-Service Chat (Subscription) Context You are asked to prepare a one-page executive brief recommending whether to ...
Write SQL for comment analytics
You are given the following schema and tiny sample data. Schema: - users(user_id INT PRIMARY KEY, country VARCHAR, created_at DATE) - posts(post_id IN...
Manipulate data in R with dplyr joins and windows
Using R and dplyr, answer the following using these small tables (dates are ISO strings): transactions(user_id, order_id, order_date, channel, amount)...
Demonstrate influential product leadership under ambiguity
Behavioral & Leadership: Influencing Without Authority Under Tight Deadlines Scenario You are a Senior Data Analyst supporting a streaming product. Fo...
Compute sample size and plan experiment
A/B Test Planning: Paywall Copy Change For New Signups Context You are planning an A/B test to evaluate a paywall copy change that targets new signups...
Diagnose and decide on watch-time drop
Hulu iOS Homepage Ranking Model Rollout: Causal Read and Decision Within 48 Hours Context - On 2025-08-25, a new homepage ranking model was shipped to...
Write complex SQL for streaming funnels
You are analyzing a Disney/Hulu product funnel with events captured in a single table. Write ANSI-SQL (Snowflake/BigQuery compatible) to answer the su...
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...
Design an idempotent churn ETL pipeline
You must build a daily pipeline that produces month-end churn metrics (logo churn, gross revenue churn, net revenue retention) from streaming subscrip...
Compute churn and revenue churn in SQL
You receive monthly end-of-month subscription snapshots and must compute August-2025 churn metrics. Schema and sample data: Table: subscription_monthl...