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"
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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."
Design experiments for marketplace product changes
You are interviewing for a Data Scientist role at a food-delivery marketplace such as DoorDash. For each scenario below, explain how you would evaluat...
How would you test a bike delivery option?
Case: Launch a bike-delivery option You work on a food delivery marketplace (customers place orders; couriers deliver). The team is considering launch...
Explain Bootstrap and Statistical Inference
Answer the following statistics questions at interview depth: - What is the bootstrap? Describe the resampling procedure, when it is useful, and what ...
How to estimate a feature’s causal impact on time spent
You work on a Roblox-like game platform. A new product change ("feature") is rolled out and you want to estimate its causal impact on user engagement,...
Measure free-month promotion impact
You are a data scientist evaluating a one-month free subscription promotion for new users. The business wants to know whether the promotion should be ...
Define Ultra success metrics and detect suspicious transactions
You work on a fintech product with these existing tables (UTC timestamps). You may only use these tables/columns; if a metric cannot be measured direc...
Choose Optimal Network Retry Threshold
You work on a mobile music streaming team responsible for improving playback reliability while minimizing battery drain. When the app is streaming aud...
How to evaluate a similar-listing notifications feature
Question You are a Data Scientist on a US C2C marketplace app (like Facebook Marketplace) where users buy and sell second-hand products. Current produ...
How would you measure product success?
You are interviewing for a Data Scientist role supporting a subscription-based collaborative design software product used by teams. The product is sol...
Design Pricing Model Experiment
You work as a data scientist for a ride-hailing marketplace. The company wants to launch a new pricing model that may change the price shown to riders...
Investigate LA Order Drop
A food delivery marketplace sees a meaningful decline in completed orders in the Los Angeles market. Explain how you would investigate the drop end to...
Estimate weather’s effect on mental health
Scenario You are studying whether weather (e.g., temperature, precipitation, sunlight, air pressure) affects mental health outcomes (e.g., depression ...
Design an A/B test for search ranking
Scenario You work on a search product and have built a new search ranking/retrieval algorithm (Variant B). The current algorithm is Variant A. You nee...
Diagnose Weekly Session Conversion Anomalies
You are a Data Scientist supporting an e-commerce platform. You receive a weekly time-series dashboard covering the past three years. The dashboard in...
Calculate Playback Counts per Stream
You are given two database tables: streamer | column | type | description | |---|---|---| | streamer_id | integer | Primary key of the streamer | | st...
Implement Plus One
Given an integer represented as an array of digits digits, where the most significant digit comes first, return the array representing the integer plu...
How would you answer a DS video interview?
Question You are interviewing for a Data Scientist Intern role at TransUnion. The technical screen is an asynchronous (one-way) video interview: you a...
Design a Maps Address Search Bar
Design the search experience for a map application's address bar, similar to the search box in Google Maps. The system should handle multiple user int...
Evaluate Overlapping Shelf Ranking Experiments
Fetch is running two A/B experiments in its mobile app. Product context The app displays product shelves. Each shelf contains multiple products, and t...
Explain KNN and how to tune it
K-Nearest Neighbors (KNN) fundamentals You are interviewing for a Data Scientist role. 1. Explain how the KNN algorithm works for both classification ...