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."
Do US members upload more videos than non-US?
You suspect video posting adoption differs between US and international members. Tables members - memberid INT (PK) - country VARCHAR (e.g., 'usa', '...
Move zeros to the front
Given an integer array nums, move all elements equal to 0 to the beginning of the array while preserving the relative order of all non-zero elements. ...
Forecast bikes available at a station
Data Analysis / Forecasting Prompt You are given historical Citi Bike (bike-share) trip and station status data. Each station has a fixed dock capacit...
Find valid range of q for outcome probabilities
You have a 3-outcome experiment with mutually exclusive outcomes: - Outcome 1 occurs with probability \(q\) - Outcome 2 occurs with probability \(q^2\...
Compute ruin probability with bold betting
Probability of Reaching 5 Tokens Before Ruin Setup - You start with 3 tokens, target is 5 tokens, and ruin is 0. - On each turn, you bet as many token...
What are linear regression assumptions?
You fit an ordinary least squares (OLS) linear regression model. 1) What are the key assumptions behind OLS (for unbiasedness and for valid inference)...
Evaluate Marketplace Changes
You are a marketplace data scientist at a mobility and delivery platform. Discuss how you would evaluate the following product and algorithm changes: ...
Collaborate with PM and Eng as DS
Question As a Data Scientist working with Product Managers and Engineers: 1. How do you structure collaboration (requirements, timelines, ownership)? ...
Compute rolling standard deviation in O(n)
Given an array of numbers and a window size k, compute the rolling standard deviation for every contiguous window. Design an O(n) algorithm that updat...
Investigate Declining Successful Orders
DoorDash observes that the number of successful orders per day in Los Angeles has declined over the last few weeks. Assume a successful order is one t...
Count Enclosed Islands in a Grid
You are given an m x n grid representing land and water after flooding. - 0 represents land. - 1 represents water. - Two land cells belong to the same...
Design a ride-hailing ETA system
During a first-round Data Scientist interview, you are asked a product and machine learning case question: Design an estimated time of arrival (ETA) p...
Compute decay, OLS, and classic probability results
You are asked several probability/statistics questions. 1) Radioactive decay (half-life) A radioactive atom has a half-life of 1 day. Assume each atom...
Compute maximum non-overlapping meetings
Assume you are given a list of meeting time intervals for a single person. Each meeting i is represented by a pair of integers [start_i, end_i], where...
Explain differences between Python list and tuple
In Python, what are the key differences between a list and a tuple? Cover: - Mutability and implications - Performance and memory considerations (high...
Implement bootstrap mean and variance
You are given an array of N numeric observations x[0..N-1]. Write a function that uses bootstrap resampling to estimate: 1. the mean of the original s...
How do you escape the circle?
A dog runs continuously along the boundary of a circle of radius 1 at speed 4. You start at an arbitrary point strictly inside the circle and can run ...
Determine Metrics to Measure Free-Trial Impact on Subscriptions
A/B Test: Free Trial Offer Impact on Subscription Behavior Scenario You are analyzing a randomized A/B test in which free users are offered a free tri...
Prioritize Tasks and Respond to Coworker Concerns
Task Prioritization and Coworker Response Simulation (Data Scientist) Context You are a Data Scientist supporting a high-traffic e-commerce recommenda...
Assess Work Authorization and Professional Experience for Job Change
Initial HR Phone Screen — Behavioral Questions (Data Scientist) Context You are in an initial HR/phone screen for a Data Scientist role. The goal is t...