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."

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"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."
Design offline backtest and online experiment
You are given an ACH transaction-level dataset to identify and control fraud and will present a plan. Today is 2025-09-01. Deliverables - Offline anal...
Measure outage impact; choose fix vs build
End-to-End Analysis Plan: Investigating Frequent Google Meet Call Drops Context A major enterprise customer reports frequent Google Meet call drops. A...
Handle extended team-matching uncertainty
Scenario: Team-Match Stall After Panel Context - You passed a company-wide panel in late February for a Data Scientist role. - First team-match meet...
Compute p-values, CIs, and adjust multiples
Hypothesis testing and intervals in practice. Part A (z vs t): You sample n = 15 observations from a population with unknown variance and observe samp...
Decide between two vendors under constraints
You have two third‑party search vendors, A and B, plus historical order‑level data: lead_time_days, unit_price, on_time_rate, defect_rate, min_order_q...
Describe a leadership STAR story
Behavioral & Leadership: Protecting Analytical Rigor Under Deadline (STAR) Context: You are interviewing for a Data Scientist role. The interviewer wa...
Drive app installs from web traffic
Increase App Installs From Web Menu Landers: Funnel, Experiment, and Measurement Plan Context A food delivery platform wants to increase app installs ...
Diagnose cold-food spike and design experiments
Cold Food Complaints: Metrics, Diagnosis, and Experiment Design Context and assumptions: - You are analyzing a spike in “food arrived cold” complaints...
Merge four CSVs locally, robustly and efficiently
You receive four CSV files that must be merged locally on a laptop with 8 GB RAM, without relying on cloud services: - products.csv: product_id, categ...
Detail NLP preprocessing and n‑gram choices
Describe your text preprocessing pipeline given the source modality: typed text, scanned/handwritten OCR, or speech-to-text. Specify language handling...
Design and sample for credit default prediction
A bank wants a model to predict 90-day credit card default at account-month level for proactive outreach. Class prevalence in production is about 2% d...
Compute sample size and test duration correctly
Powering Two Online Experiments: Sample Size, Duration, and Design Defenses You are designing experiments to improve a friend-accept rate metric in a ...
Address face recognition concerns with stakeholders
Case Prompt: Face Recognition for Cardholder Verification at POS You are interviewing for a Data Scientist role and are asked to evaluate a proposal t...
Explain p-value and choose correct test
Technical Screen: P-values and Robust Two-Sample/Paired Tests Context: You are a data scientist evaluating healthcare interventions. Answer in clear, ...
Explain your ML project end-to-end
End-to-End ML Project Deep Dive (7 Parts) Assume you are describing the most complex ML project on your resume. Answer each part precisely and concret...
Choose tests under non‑normal, unequal variance
Heavy-Tailed, Heteroskedastic Metrics in A/B Tests (AOV example) Context: You are comparing two groups in an A/B test on a spend metric (e.g., Average...
Solve stock, BFS path, and merge intervals
Solve three coding problems; justify complexity and corner cases. A) Best Time to Buy/Sell Stock (one transaction): Given prices[0..n-1] (integers), r...
Compute profit and surge break‑even price
Capacity and Break-even Pricing for a Ride-share Service Context: You manage daily capacity and pricing for a ride‑share service. Each driver works an...
Rank factors for TikTok market entry
TikTok Market Z Launch Decision Framework (Q4 2025) Context You are a data scientist evaluating whether TikTok should launch in a new country (Market ...
Optimize attempts in a timed logic test
Timed OA: Maximize Expected Score Under a Time Limit Context: You have 25 minutes (1,500 seconds) to attempt up to 30 multiple-choice items. You may c...