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 expected value of simple gambling games
You are asked two probability/EV questions. 1) Dice game expected value / fair entry fee A game works as follows: - You pay an entry fee of \(c\) doll...
Diagnose metric anomalies and evaluate new algorithm
Context You work on a consumer product that includes an AI calling feature (users trigger calls; the system places AI-assisted calls). The team monito...
Remove shortest subarray to sort array
Given an integer array nums (length up to 2×10^5), return the shortest subarray [L,R] you can remove so that the remaining elements form a non‑decreas...
Design and validate an ads feed experiment
Experiment Design: Redesign of Feed Ranking and UI for an Ad‑Supported Mobile News App Context You are the first data scientist on a mobile news app m...
Write SQL to analyze shop visibility
You are given two tables. Use standard SQL (window functions allowed). Assume "today" is 2025-09-01 and that “currently visible” means a shop’s last s...
Design bot detection and evaluate trade-offs
Bot-Detection System Design for Comment Activity Context You are designing and evaluating a machine learning system to detect automated (bot) comment ...
Dissect a failure and corrective actions
Describe a recent failure. Explain: a) root causes (your decisions vs. external factors) using a 5 Whys or fault-tree; b) early warning signals you mi...
Describe your proudest accomplishment and impact
What is the most meaningful accomplishment in your recent role? Detail: a) the baseline and measurable target; b) constraints and risks; c) your uniqu...
Design analysis to test social vs game engagement
Question Hypothesis: Among Oculus (Meta Quest) users, those who use social features are more regularly engaged than those who use game features. Using...
Write SQL for daily chats and fast replies
You are given a messaging events table that records one row per message sent. Schema - messages( date DATE, -- calendar date of event (UTC) ts TIMES...
Define and query shop visibility
You are given the following schema. Use only the columns provided; do not introduce new fields or labels. Tables and columns: - shops(shop_id INT, sho...
Build and evaluate illegal-video classifier
End-to-End ML System Design: Flag Illegal YouTube Videos You are tasked with designing a production ML system to detect and triage potentially illegal...
Design long-tail search evaluation under label budget
Estimating ΔNDCG@10 With Limited Labels Under a Heavy-Tailed Query Mix You serve ~100M queries/day. Query frequencies follow a Pareto distribution wit...
Write SQL to monitor weekly chargeback spikes
Write a single SQL query (PostgreSQL) to detect weekly chargeback spikes by country and industry. Week starts Monday (use date_trunc('week', ts) with ...
Describe an accomplishment with quantified impact
Describe one professional accomplishment you are most proud of from the past two years. Make it audit-ready by covering: goal, measurable target, cons...
Implement percentage RMSE and bootstrap its CI
Given a CSV with columns [country, actual_revenue, predicted_revenue], define percentage RMSE as pRMSE = sqrt(mean_i((pred_i/actual_i − 1)^2)). a) Imp...
Assess education–income effect credibly
You collected data on 1,000 Mountain View residents: College (binary; attended any college) and Income (annual). Is regressing Income on College alone...
Test if one value comes from N(μ,σ²)
Assume the population is N(μ, σ²) with μ and σ known. You observe a single value x = 1.37. Formulate a two-sided hypothesis test H0: X ~ N(μ, σ²) vs H...
Describe toughest project and align stakeholders remotely
Describe the single most challenging data science project you led end-to-end in the last 24 months. In 90 seconds, state: the business goal, exact sco...
Compare Tableau live vs extract and filters
Scenario You are building an interactive dashboard over a 100M-row fact table. Compare Tableau connection options and performance behaviors for this s...