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."
Find multi-account buckets and unread rate
You are analyzing a product in which one user can own multiple accounts. Use the following schema: Table: accounts - account_id BIGINT - user_id BIGIN...
How do you lead and drive impact?
You are interviewing for a senior or tech-lead data scientist role. Prepare to answer the following behavioral prompts with concrete examples from you...
Describe a time you solved a complex problem
Behavioral (Leadership/Ownership): Describe a time when you solved a complex problem by digging into details. In your answer, cover: - The context and...
Implement composition and mixin utilities
Solve the following two Python tasks. Part A: Implement function composition Implement a Python function compose(*funcs) that: 1. Accepts any number o...
Compute expected counters after color elimination
Compute expected counters after color elimination Problem You have a bag with 30 counters: 10 red, 10 yellow, and 10 blue. You draw counters uniformly...
Find Longest Increasing Continuous Subarray
Given an integer array nums, return the length of the longest contiguous strictly increasing subarray. "Contiguous" means the elements must appear nex...
Present an A/B test project review
Onsite Project Review: Analyze and present an A/B test Before the onsite, you completed a take-home project analyzing an A/B test (you can assume typi...
Design an experiment for exploratory recommendations
Experiment Design for Exploratory Recommendations You are launching an online A/B test for a new recommendation algorithm. The goal is to increase use...
Identify User Interest in Group Video Calls Using Data
Identify User Interest in Group Video Calls Using Data You are designing and analyzing a new group video-calling feature for a large social or messagi...
How to Validate Friends' Content Engagement Hypothesis?
Validate Friends' Content Engagement Hypothesis A Meta product team wants to know whether content from a viewer's friends or connected authors drives ...
Evaluate Impact of Targeting Ads to High-Intent Users
Evaluate Impact of Targeting Ads to High-Intent Users A product manager proposes allocating all ad impressions to users predicted to be high intent, a...
Master A/B Testing: Key Concepts and Methodologies Explained
A/B Testing and Causal Inference: Core Concepts You are a data scientist interviewing for a role working on an online product. Demonstrate practical A...
Identify SQL Joins and Correct Query Errors
Winner +----+-------+ | ID | Name | +----+-------+ | 1 | Alice | | 2 | Bob | | 3 | Carol | +----+-------+ Loser +----+-------+ | ID | Name | ...
Calculate Expected Meetings in Randomly Assigned Rooms
Expected Meetings in Randomly Assigned Rooms You are solving two probability questions about room occupancy. Constraints & Assumptions - In the first ...
Evaluate Soft Skills Through Behavioral Interview Questions
Behavioral and Leadership Interview: Soft Skills You are interviewing for a Data Scientist role in an onsite Behavioral and Leadership round. Prepare ...
How to Design Effective A/B Tests for Onboarding
Design Effective A/B Tests for Onboarding A consumer subscription app is launching a redesigned onboarding flow for newly registered users. The goal i...
Optimize Station Sequence for Maximum Car Output in Simulation
Scenario The Car-Building mini-game lets you sequence chassis, engine, and paint stations with limited buffers. Question Describe a strategy to maximi...
Calculate Expected Day for First Selection in Sampling
Expected Day of First Selection in Daily Sampling There are 1,000 people. Each day, 10 distinct names are selected uniformly at random. Day counting s...
Investigate Traffic Distribution Impact on Retention Decrease
A/B Test Diagnostics: Traffic Distribution and Retention Drop An A/B test changed a button color from green in control to red in treatment. The primar...
Predict Customer Churn with Machine Learning Workflow
Predict Monthly Customer Churn With an End-to-End ML Workflow A subscription platform wants to predict whether a customer will churn in the next month...