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."
Solve two string DP/hash problems
Solve the following two coding questions. 1) Unique Morse Code Transformations You are given an array of strings words (lowercase English letters). Us...
Write SQL for repeat churn
Write a SQL query to measure the performance of a free-month promotion experiment. Assume experiment_users already contains only users who were eligib...
Compute per-coin quarterly amounts and totals
Problem (SQL: Conditional Aggregation) You have two tables: coins - coin_id INT PRIMARY KEY - name VARCHAR transactions - id BIGINT PRIMARY KEY - coin...
Present Piracy Trends to a PM
You ran the analyses above and got two preliminary findings: - the monthly pirated-theme usage rate appears to rise from 0% to 100% over the observed ...
Estimate Two Conditional Win Probabilities by Simulation
Estimate Two Conditional Win Probabilities by Simulation You are given a game with three closed doors, labeled 0, 1, and 2. Behind exactly one door is...
Find top-5 most similar rows across datasets
You can solve this in SQL or Python. You are given two datasets with the same feature columns: Tables target_rows (rows you want to match) - target_id...
Compute active ad revenue by creation source
You work on an ads platform and need to report active ad revenue broken down by the ad’s creation source. Tables ads - ad_id BIGINT PK - advertiser_id...
Query and transform marketplace data in SQL/Python
Assume today is 2025-09-01. Use the following schema and sample data to answer the questions with both SQL (preferred) and equivalent Python (pandas) ...
Explain why LASSO selects features
Explain why LASSO performs feature selection. Provide: 1) high-level intuition comparing L1 vs. L2 penalties; 2) geometric interpretation of the const...
Write SQL for visibility, calls, and cohort activity
You have the following schema and toy data. Assume "today" = 2025-09-01. users(user_id INT, signup_date DATE) Sample: user_id | signup_date -------...
Calculate survey response and quality metrics in SQL
Compute survey response-rate and quality metrics from event data. Assume "today" = 2025-09-01, and compute over the last 7 days (2025-08-26 to 2025-09...
Write SQL to compare exclusive category engagement
You are given session-level data and must compare engagement between users who exclusively used the 'social' category versus those who exclusively use...
Aggregate weekly revenue and attribute 4% drop
Write SQL over the following schema to: (A) compute weekly revenue by ISO week (Monday–Sunday) from orders, excluding cancelled/refunded; revenue_usd ...
Audit flight data quality from metadata
You’re given an airline on‑time dataset and a one‑page “Metadata” slide that claims: flight_date (string, local time), dep_time/arr_time (HHMM local),...
Write SQL to localize anomaly and funnel
Given the schema and toy data below, write SQL to (a) validate instrumentation vs behavior change, (b) localize the 2025-09-01 Likes drop by app_versi...
Transform retail data with pandas groupby/merge/concat
Using pandas only (groupby/agg/merge/concat; no for-loops), write code to answer the sub-questions below on the following small dataframes. Assume tim...
Write SQL to localize trading drop contributors
Use the schema and samples below. Unless stated, treat a user as active on a day if they attempted any order (any status). Dates are inclusive. Schema...
Build a cohort dashboard with Streamlit and SQL
You are given three tables and asked to build a minimal Streamlit app that helps a PM explore weekly cohort retention and ARPU by country. Assume SQL ...
Compute last-to-previous ad impression gaps
Given impressions(ad_id INT, user_id INT, impression_ts TIMESTAMP) with multiple impressions per (user_id, ad_id), write a single SQL query to return,...
Compute per-player daily cumulative games with windows
Write a SQL query to output, for each player_id and each calendar date present in the data, the cumulative number of games played up to and including ...