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 an ML project end-to-end with tradeoffs
Pick one of your production ML projects and walk through it end-to-end. Be specific: 1) Problem framing (prediction vs causal decisioning), target def...
Test two models' proportions for significance
Two search models, A and B, were each used once by 100 distinct users (one query per user). Success is defined per query by your composite metric (suc...
Implement streaming k-way merge with constraints
Implement a function merge_k(iterators, N) that returns the first N items of the global ascending order from k sorted, potentially unbounded iterators...
Design and analyze pricing-page A/B test
AB Test Plan: New Pricing-Page Layout Context: You will run a 2-arm online experiment on a pricing page. The primary metric is user-level paid convers...
Identify and mitigate risks to break-even
Break-even Risk Assessment for the RH Partnership Offer Context You are evaluating a break-even (BE) analysis for a partnership offer with RH (e.g., a...
Compute survey rates and bias-correct ratings
Today is 2025-09-01. Use the schema and sample data below to answer A and B with SQL (standard SQL; you may use CTEs and window functions). Assume tim...
Review checkout code for defects and privacy
You are reviewing a supermarket checkout implementation. Identify and prioritize issues and fixes across: (a) monetary correctness (avoid floating poi...
Design enterprise file recommendations under ACLs
Design a system to recommend to a signed-in enterprise user the next files they are most likely to open in a productivity suite. Cover: (1) key signal...
Interpret regression metrics and assumptions
A multiple linear regression is fit to predict arrival delay with standardized numeric predictors and one‑hot categorical variables. Without seeing th...
Design an A/B launch amid marketing confounds
You’re running a virtual launch (soft roll-out) of a new fitness tracker product to US+CA users from 2025-08-10 to 2025-08-24 with a 50/50 user-level ...
Explain grocery-specific product strategy and scrappy XP
Launching Grocery Delivery in NYC: Product and Experimentation Plan Context A delivery platform that is strong in restaurant delivery is launching a g...
Implement anagram check and stable deduplication
Part A — Anagram checker: Write a function is_anagram(a: str, b: str, locale: str = 'en') -> bool that returns True iff a and b are anagrams under the...
Evaluate Facebook Dating launch and validate success
Validation Plan: Scaling Facebook Dating from Pilot to Broader Rollout Context: You are a data scientist evaluating whether a limited-market pilot of ...
Design and evaluate an uplift model
Targeting a 20% Subset With a Free-Delivery Promotion to Maximize Incremental Orders per Dollar Context You work on a two-sided delivery marketplace a...
Handle challenges in MMM/MMX
MMM Fragility Diagnosis and Remediation Plan (Weekly, 156 Weeks) Context You inherit a weekly Marketing Mix Model (MMM/MMX) with 156 weeks of data. Th...
Analyze A/B test with revenue–cost tradeoffs
A/B Test: Same‑Day Delivery Checkout Change You are evaluating a checkout UI change that promotes same‑day delivery. The experiment is a standard two‑...
Compute A/B sample size under clustering
A/B Test Sample Size With Unequal Allocation, Clustering, and Attrition Context You are planning a two-arm signup A/B test (binary outcome: convert vs...
Design a profit growth strategy
Ride-share Profit Plan (Next Quarter) Context You are the data scientist for a ride-share marketplace (two-sided: riders and drivers). Your goal is to...
Diagnose and fix flawed model fit
Fixing a Churn Classifier: Encoding, Imbalance, Evaluation, and Fairness Context You inherit a binary classifier that predicts churn=1. The current im...
Explain life-story choices and pre-read insights
HR Screen Pre‑read and Life Story Exercise (Data Scientist) Context You receive a 6‑page HR pre‑read 24 hours before a 60‑minute "Life Story" intervie...