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."
Explain power drivers and resolve unexpected A/B results
A/B Testing: Power, Sample Size, Allocation, and Diagnostics You are analyzing a two-proportion (binary conversion) A/B test with independent users, n...
Explain SHAP vs VIF under collinearity
High Collinearity in Binary Classification: VIF, SHAP, and Interpretation Strategy You are modeling a binary outcome Y. Two numeric features A and B a...
Solve probability and expectation problems
Probability and Expectation Practice (Take‑home) Assume all coins and dice are fair unless stated otherwise. Show reasoning and final results. 1) Thre...
How to experiment on ETA reduction
Context You work on a consumer app where users see an ETA (estimated time to arrival/delivery) during a funnel (e.g., browsing → checkout → order plac...
Should WhatsApp Launch Group Calls?
Assume WhatsApp currently supports only 1:1 audio and video calling and is considering launching group calling. You are the data scientist evaluating ...
Count Same-Day Registered Posters
You are given two tables: `text users - user_id: unique identifier for a user - registered_at: timestamp when the user registered posts - post_id: uni...
How to validate production models?
You are interviewing for a fintech model-validation team that acts as a second line of defense for credit-risk and fraud models. A hiring manager asks...
Evaluate AI-assisted ad creation
Meta is considering launching an AI-assisted ad creation feature for advertisers. The feature helps advertisers generate ad copy and/or creatives insi...
Calculate Cohort Retention
You are given two tables: users - user_id BIGINT PRIMARY KEY - signup_ts TIMESTAMP user_events - user_id BIGINT - event_ts TIMESTAMP - event_name VARC...
Predict Future Car Sale Prices
You are given transaction-level data from car dealers for calendar year 2018, and you need to predict vehicle sale prices for transactions that will h...
Test whether US uploads more videos
You want to evaluate the hypothesis: > “US members upload more videos than non‑US members.” You have: Table: video_posts | column | type | |---|---| |...
How would you evaluate adding video ads?
You are a data scientist for a free-to-play mobile game. The product team wants to introduce video ads (e.g., rewarded videos and/or interstitial vide...
How would you forecast bike demand?
You are given historical data from a shared city-bike system and asked to predict usage for a specific docking station during the next hour. Assume yo...
Merge two sorted linked lists
Given two singly linked lists sorted in ascending order, merge them into one singly linked list that is also sorted in ascending order. Requirements: ...
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...
How predict vehicles’ turn direction at intersection?
At an intersection, there are N vehicles stopped or moving slowly. For each vehicle you have historical time-series data up to the current time: - Pos...
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...
Return the largest file size in a directory
Problem (Bash / File System) Implement a Bash function (or shell snippet) that returns the maximum file size (in bytes) under a given directory. Requi...
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...
Explain PCA and L2 Normalization in Machine Learning
Scenario Experian DataLabs Data Scientist technical screen — a machine-learning deep-dive on the modelling choices used in your project, mixed with co...