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."
Merge and Concatenate Inconsistent Order Files with Pandas
orders_2023 +----------+-------------+--------+ | order_id | customer_id | amount | +----------+-------------+--------+ | 101 | C001 | 120...
Clean and Summarize User Purchase Data Efficiently
transactions +-----------+---------------------+-----------+--------+ | user_id | txn_timestamp | txn_value | txn_id | +-----------+----------...
Optimize Experiment Thresholds for Impactful Feature Launches
Scenario You are the data scientist for a consumer health product running ~100 concurrent A/B tests under tight timelines and limited traffic. Leaders...
Mitigate Data Mistakes and Improve Team Efficiency
Behavioral Questions (STAR Format) Context: You are interviewing for a data role at Amazon, where leadership principles and measurable impact matter. ...
Calculate User Revenue and Session Duration in Python
events +---------+------------+---------+---------------------+ | user_id | event_type | revenue | timestamp | +---------+------------+-----...
How to Update Bayesian Model for Concept Drift?
Beta–Binomial CTR Model: Prior, Likelihood, Posterior, Smoothing, Intervals, and Drift Context You are discussing statistical foundations for a Bayesi...
Why Join Moloco: Your Career Aspirations and Goals
Behavioral: Motivation and Role Fit (HR/Phone Screen) Context You are interviewing for a Data Science Intern position at Moloco during an initial HR/p...
Analyze Acquisition Channels for User Value and Retention
acquisition | user_id | acquire_channel | acquire_date | | 101 | organic | 2023-01-05 | | 102 | paid_search | 2023-01-06 | | 103 | social_media | 2023...
Analyze Ad CTR and Convert Transactions to USD
AdsImpressions +-----------+---------+------------+--------+-----------+ | user_id | ad_id | impressions| clicks | event_dt | +-----------+------...
Improve YoY Revenue Analysis with Complementary Metrics
ads_revenue +------------+-----------+ | date | revenue | +------------+-----------+ | 2023-01-01 | 120000 | | 2023-02-01 | 125500 | | 2...
Resolve Ties for Top-10 Users in SQL Query
Oculus_Scores +---------+-------+ | user_id | score | +---------+-------+ | u1 | 95 | | u2 | 92 | | u3 | 90 | | u4 | 90 ...
Calculate User Deviation from Team Average Messages
usage_stats +---------+---------+---------------+------------+ | user_id | team_id | messages_sent | date | +---------+---------+---------------...
Measure Pirate-Theme Usage and Revenue Growth Over Time
theme_usage +-----------+------------+-------------+ | user_id | theme_name | created_at | +-----------+------------+-------------+ | 101 | p...
Identify Top Three Active Users by Event Date
event_log +------------+---------+-----------+---------------------+ | event_date | user_id | event_type| event_timestamp | +------------+--------...
Assess Leadership Through Disagreement, Failure, and Risk Examples
Behavioral Leadership Deep-Dive (Data Scientist Onsite) Scenario A leadership-principles deep-dive will assess ownership, bias for action, and learn-a...
Explain Treatment Results and Recommend Launch Criteria for Experiments
A/B Test Interpretation, Launch Decision, Segmentation, and Multiple-Testing Control Context You ran an experiment with two treatments (t1, t2) agains...
Navigate Crises and Sustain Team Morale Under Pressure
Behavioral & Leadership — Data Scientist Onsite Scenario You are working as a Data Scientist on a product-facing team. Mid-project, a major risk or cr...
Identify Features for Fake News Detection on Facebook
Design a Machine-Learning System to Flag Fake News on Facebook Scenario An increase in fake news has been detected on the platform. You are asked to d...
Determine Discount's Effect on Conversion Rate with A/B Testing
A/B Test Design: 10% Discount Impact on Conversion Scenario An e-commerce retailer wants to evaluate whether offering a 10% sitewide discount increase...
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 |...