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."
Estimate laptops in an office
Give a back-of-the-envelope estimate for how many laptops are physically present in a typical corporate office at a given moment. State your assumptio...
Predict Bike Dock Demand
You are working on a docked bike-sharing system. Build a model that predicts how many bikes will be checked out from a specific dock in the next hour....
Merge Two Sorted Lists
You are given the heads of two singly linked lists, each already sorted in non-decreasing order. Merge them into one sorted linked list and return the...
Implement bootstrap mean and variance
Given an array of N numeric values, implement a function that uses bootstrap resampling to estimate the sampling distribution of the mean. The functio...
Measure Shopify App Store Launch Success Effectively
Scenario Shopify is launching the Shopify App Store to help merchants discover, evaluate, and install third‑party apps that extend their stores. Task ...
Evaluate Piecewise Linear Function
Given a list of 2D points [(x1, y1), (x2, y2), ..., (xn, yn)], where the points are ordered by strictly increasing x, connect each consecutive pair of...
Why use the t-statistic?
In an A/B test or any mean-comparison setting, explain why the t-statistic is a useful measure. Your answer should cover: 1. What the t-statistic meas...
Determine When a Quadratic Has Finite Minimum
Consider the unconstrained real-valued optimization problem \[ \min_{x \in \mathbb{R}^n} f(x) = x^\top Qx + c^\top x, \] where \(Q \in \mathbb{R}^{n \...
Determine departure time from travel times
Canoe and River Current Timing Context Two friends paddle on a river with a constant current of 2 mph. Their paddling speed relative to the water is c...
Evaluate a credit-card acquisition partnership
Cohort NPV and Sensitivity for New Credit-Card Customers Context You are evaluating a co-branded partner expected to deliver 50,000 newly acquired cre...
Design an experiment for thermal bags
Experiment Design: Thermal Bags for Couriers to Reduce Cold-Food Refunds Background We want to evaluate whether providing couriers with thermal bags r...
Describe past project experience clearly
You are interviewing for a Data Scientist Intern role in an asynchronous video interview format. Prepare concise, structured responses to the followin...
When do you use mixed-effects models
You are modeling a user outcome (e.g., watch time or retention) across many countries and many users. Observations are nested (multiple days per user;...
Evaluate Groupon's Impact on Restaurant's Profitability and Strategy
Scenario You own a restaurant, and a Groupon-style deals website proposes selling discount vouchers (coupons) for your venue. You must decide whether ...
Compute each member’s current notification status
Question You are given two tables describing LinkedIn members’ push-notification settings. Compute each member’s current notification status as of 202...
Review Preprocessing Code and Tests
You are reviewing a small Python preprocessing codebase during an interview. You do not need to write code. Part A: Environment and execution A shell ...
How would you mentor junior teammates?
Question You are interviewing for a senior-level data science role at DoorDash. The interviewer asks: > As a senior, how would you mentor others (espe...
Design Identity-Trust A/B Test
You are interviewing for a Data Scientist role on an Identity & Trust team at a consumer product company. The team wants to launch a feature that stre...
Calculate a Confidence Interval
Suppose an online experiment compares treatment and control on conversion rate. Treatment has x1 conversions out of n1 users, and control has x0 conve...
How to target commute coupon users?
You are a Data Scientist on the commute team at a ride-sharing company such as Lyft. The team wants to launch a coupon campaign to increase usage of c...