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."
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"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."
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"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."
Test If Initial Video Uploads Are Shorter Than Later Ones
Hypothesis Test: Are Users’ First Video Uploads Shorter? Context You are given event-level data for a video-sharing product. Each record represents a ...
Determine Circle Intersection Status for Rendering Order
Scenario Graphics engine must evaluate multiple pairs of circles to decide rendering order based on intersection. Question Given an array where each e...
Design Incremental Load Process for Large Relational Table
orders_daily_load +------------+-----------+-------------+--------+ | load_date | order_id | customer_id | amount | +------------+-----------+------...
Employ Collaborative Filtering for Personalized Recommendation Lists
Scenario You are releasing a new recommendation feature that must generate and assign personalized, ranked product lists for each user at scale. Users...
Analyze Impact of Customer Reviews on Sales Performance
Measuring the Impact of Product Reviews on Sales Context You are asked to propose how to quantify and causally estimate the impact of product review m...
Calculate Weekly, Monthly Watch Hours for Paid Users
video_view_logs +---------+----------+----------------+------------+------------+ | user_id | video_id | watched_seconds| watch_date | device_type| +-...
Define Metrics and Account for Network and Novelty Effects
Evaluating Notification-Triggered In-App Surveys Scenario Meta’s notification system triggers optional in-app surveys to measure user sentiment after ...
Analyze Distribution of Daily Page Shares Per User
Engagement Distributions and Cohort Dynamics You are analyzing per-user, per-day engagement. Assume a day-level panel with all users included (inactiv...
Calculate Probabilities for Mixed Reviewer Types
Scenario Two types of reviewers exist in a marketplace: - Lazy reviewers (20%) always give good reviews. - Careful reviewers (80%) give good reviews 6...
Calculate 7-Day Rolling Average for Energy Consumption
Scenario Hiring manager wants a quick coding exercise to verify programming fluency. Question Write a Python function that takes a list of daily energ...
Build Predictive Model for Product Metric: Steps Explained
Scenario You are interviewing for a Data Scientist role and are asked to design a predictive model for a key product metric in a consumer app (e.g., p...
Single Queue vs Multiple Queues — Service Design
Bank Branch Queue Design: Single Line to c Tellers vs c Independent Lines Context and assumptions for comparability: - Arrivals are approximately Pois...
Evaluate Metrics for Restaurant-Feature Impact and Engagement Trade-offs
Product Analytics Case: Restaurant Recommendations vs. New-Friend Suggestions Background You are a data scientist at a large social app. The app launc...
Analyze Revenue Shifts to Identify Cannibalization Effects
Cannibalization vs. Organic Growth Across Creation Sources Scenario Management observed strong revenue growth from one creation_source (a channel by w...
Analyze User Flags and Review Outcomes for Moderation Prioritization
UserFlags +---------------+--------------+----------+---------+ | User_FirstName| User_LastName| Video_ID | Flag_ID | +---------------+--------------+...
Identify First Daily Order for Each Merchant
Orders +----------+-------------+---------+------------+ | order_id | merchant_id | amount | order_date | +----------+-------------+---------+-------...
Identify and Fix Predictive Model Performance Gaps
Model Review: Month Encoding, Feature Scaling, and Imbalanced Data Context You are auditing an existing predictive model for operational performance. ...
Maximize Distinct Purchases Within Budget Constraints
Scenario Given a customer budget and a list of product prices, determine the maximum number of distinct products the customer can afford. Question Des...
Analyze Factors Behind 20% Retail Revenue Decline
Retail Revenue Decline Analysis Scenario A retailer reports a 20% decline in revenue compared with a prior, comparable period. Assume revenue is net o...
Count, Return, Find, and Select in SQL Queries
orders +----------+--------------+------------+--------+ | order_id | customer_id | order_date | amount | +----------+--------------+------------+---...