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."
Generate primes up to n efficiently
Implement a function that returns all prime numbers in the inclusive range 1..n. Requirements: handle n up to 10^7 efficiently (time and memory); retu...
Compute profit and decompose Groupon impact
You run a restaurant with these economics: baseline demand is 20 tables/day, average revenue is $30/table, variable cost (VC) is 40% of revenue, and f...
Demonstrate leadership in data ambiguity
Describe a time you inherited an underperforming metric or model, disagreed with the team’s preferred fix, yet had to recommend a decision under a tig...
Compute CTR and metrics with pandas
Using pandas only, compute banner and story metrics. Assume today is 2025-09-01 and 'last 7 days' means 2025-08-26 to 2025-09-01 inclusive. You are gi...
Derive logistic regression and thresholds
Logistic Regression Deep Dive (Binary Classification) Assume a binary classification setting with observations {(x_i, y_i)} for i=1..n, where x_i ∈ R^...
Prove reservoir sampling correctness
Design an algorithm to sample k items uniformly at random from a stream of unknown and potentially massive length N, using O(k) memory and one pass. (...
Contrast L1 and L2 regularization effects
Ridge (L2) vs Lasso (L1) in Linear and Logistic Regression Context: You are comparing L2 (Ridge) and L1 (Lasso) regularization for linear and logistic...
Evaluate Miami Ultrafast impact on orders
Instacart launched an Ultrafast delivery feature in Miami two months ago. You have weekly orders per geo for the past 52 weeks; Miami is treated from ...
Determine if players prefer local creators without experiments
You cannot run an A/B test. Define “local creators” as creators whose games use a player’s native language. Design an observational study to estimate ...
Contrast FCF vs NI; choose one statement
An asset-heavy company reports rising net income while free cash flow (FCF) is negative for three straight quarters. a) Explain when and why FCF can b...
Demonstrate fit with quantified stories and motivations
Behavioral & Leadership Technical Screen Prompt (Data Scientist) Provide two stories—one professional and one personal—that demonstrate you’re a stron...
Compute A/B significance, CI, and power
You run an A/B test for 7 days. Control A: 520 conversions out of 10,000 sessions. Variant B: 630 conversions out of 11,500 sessions. Use a calculator...
Optimize profitability for coding contract decisions
A client offers two mutually exclusive fixed-price projects starting 2025-10-01 with a hard deadline of 2025-10-31. Your current team has 3 engineers....
Explain a project and justify choices
Walk me through your most impactful project end-to-end: what problem and success metric did you define, what alternatives did you evaluate and reject,...
Answer rapid-fire leadership checklist
Answer a rapid-fire leadership checklist: (a) Describe a time you protected customer privacy under executive time pressure—what did you refuse to log ...
Build a causal ML pipeline end-to-end
Policy Targeting from Causal Inference to Production Context You completed a causal-inference project estimating the effect of a binary marketing trea...
Design classification under missingness and imbalance
30-Day Readmission Classifier: End-to-End Plan Context: You are building a binary classifier to predict 30-day readmission using claims and EHR featur...
Diagnose Sunday Miami same‑day outages
Marketplace stability case: same‑day disablement on Sunday afternoons (Miami) Context Instacart offers two fulfillment modes: - Same‑day delivery (rea...
Design an interference-robust A/B test for monetization
A/B Test Design: New Tipping UI on Creator Posts Context: You are launching a new tipping UI on creator (PGC/OGC) posts to increase creator monetizati...
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...