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."
Compute join counts and window ranks
Given the following small schema and data, answer all parts precisely and justify each count/output. Tables and rows: Customers(cust_id INT PRIMARY KE...
Calculate profit and break-even across pricing models
Unit Economics and Break-even Analysis for a Cloud-Storage Startup You are analyzing a cloud-storage startup that currently charges unit-based pricing...
Diagnose profit drop via mix decomposition
Profit Decomposition, Attribution, Experiment Design, and Diagnostics Context and Assumptions (to make the task self-contained) We analyze why daily p...
Lead innovation and automate a critical process
Describe a specific project where you led an end-to-end innovation from idea to production. Be concrete: - What was the problem, constraints, and succ...
Build a leak-free sklearn churn pipeline
Take‑Home ML Task: Reproducible Subscription Classification Pipeline You are given a daily user-level dataset and must build a reproducible Python (sc...
Decide and test a 20% discount strategy
Case: Evaluate a 20% Discount Campaign Context Marketing proposes a 20% discount to boost purchases. You are asked to build the business case, design ...
Evaluate and test a Top Dasher program
Top Dasher Program: Decision Framework, Experiment with Interference, Anti-Gaming, and Ethics Context You are a data scientist at a food delivery mark...
Design incrementality test for TikTok ads
Design an Incrementality Test to Prove TikTok Ads Drive Lift in Conversions You are an advertiser who wants to causally prove that TikTok ads increase...
Explain AUC, activations, ensembles, and imbalance
Machine Learning Metrics and Modeling Choices — Multi-part You are given model scores and binary labels for a small dataset and asked to compute ROC A...
Implement rotated array binary search with duplicates
Given an integer array nums that is a non-decreasing array rotated an unknown number of times. Duplicates may exist. Implement a function that returns...
Measure fake-news interventions under network interference
Experiment Design Under Interference: Warning Label for Suspected Fake-News Reshares Context You are testing a pre-reshare warning label for links sus...
How would you explain PCA and SHAP?
Question You are interviewing for a Data Scientist role at Point72, a systematic / quantitative investment firm. The interviewer asks you to pick one ...
How to rank statements by likelihood
You are given a "likelihood" / "data interpretation" test. For each question: - You are shown a data representation (e.g., a large table, a scatter pl...
Answer core probability and inference questions
You are interviewing for a Data Scientist role. Explain/derive the following statistics fundamentals. 1. State the Central Limit Theorem (CLT). What c...
Design a short-video recommender system
ML System Design — Short-video recommendation Design an end-to-end recommendation system for a short-video feed (TikTok/Reels-style). Walk through the...
Convert Dictionary to DataFrame
Using Python and pandas, convert the following dictionary into a DataFrame. Each top-level key is a target column name, and each value is a list of [r...
How would you evaluate causal lift and a paywall change?
Question You are interviewing for a Data Scientist role at a consumer subscription platform (a two-sided social/dating app) that also runs an advertis...
Present pirated-usage findings to a PM
You computed (1) monthly % of shops using pirated themes and (2) monthly and cumulative estimated revenue loss from pirated themes. Explain how you wo...
Model wins-until-failure and expected future wins
You are given a DataFrame df where each row summarizes a player’s performance until their first loss. Input df columns: - player_id (string/int) - win...
Should We Launch Group Calling?
Question You work on a consumer calling product (think Messenger/WhatsApp-style voice) that currently supports only one-to-one voice calls. The team i...