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.
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"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."
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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."
Walk through a DS project end-to-end
Prompt Describe one data science / analytics project you worked on, end-to-end. What to cover Include concise but concrete details on: - Problem & goa...
Relate coefficients under linear feature transformation
Suppose you are fitting a linear regression model and you consider two different feature parameterizations. Original features: x1, x2. Transformed fea...
Find top-5 most similar rows across datasets
You are given two datasets with the same feature columns: - source (rows you want to match): - source_id (STRING/INT) - f1...fk (NUMERIC; may cont...
Solve queue switch and coin change puzzles
This entry contains two separate interview-style quantitative/algorithmic questions. --- 1. Queue switching decision problem You are standing in a sin...
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...
Estimate bots and CI from DAU spike
Mixture Spike and Mean-Difference Inference for Daily Comments Context A product has DAU (daily active users) = 2,000,000. On day T, total comments in...
Describe challenge, influence, and mentorship outcomes
Answer three parts using the STAR method and concrete metrics: (1) Most challenging project: what was the goal, constraints, and your specific ownersh...
Design offline segments for Meta Portal retail
Meta Portal is a plug‑in home video‑calling device sold via offline retail. Target segments are not finalized. You have historical, anonymized Faceboo...
Size opportunity for new product line
An e-commerce site considers adding a "Home Office" product line. Before any A/B test, size the opportunity and recommend whether to proceed. Assumpti...
Diagnose a sudden KPI drop
On 2025-09-01, a global social network observes a 10% decline in daily Likes per DAU versus the prior 4-week same-weekday baseline. Walk me through a ...
Deliver self-intro and justify move and company fit
Behavioral Prompt: Self‑Introduction, Why Capital One, and Job‑Change Rationale Context You are interviewing for a Data Scientist role during an HR sc...
Compute expansion profits and expected value
Theme Park Expansion Profit Analysis Context You are evaluating the financial impact of capacity expansion for a theme park. Current operations and pr...
Present and defend your data challenge end-to-end
10–12 Minute Interviewer-Driven Walkthrough: Recent Data Challenge Provide a concise, structured walkthrough of a real project you led end-to-end. Ass...
Assess card rewards profitability and break-even spend
Credit Card Unit Economics and Break-even Spend Context A bank is evaluating launching a credit card that pays 1% rewards on all purchases. Consider p...
Design an idempotent SQL ETL for late data
You own the daily_user_metrics fact table. Build an idempotent, rerunnable ETL that can be triggered for any date D and correctly handles duplicates, ...
Compute unit economics and insurance break-even
Subscription unit economics and insurance math. Assume no discounting and ignore taxes unless stated. Part A (15-month term): A subscription service c...
Compute precision–recall curve on imbalanced data
You receive a CSV with columns: actual_label ∈ {0,1} and predicted_prob ∈ [0,1]; the positive class rate is ≈5%. a) Which evaluation metrics would you...
Establish causality: commute playlist and driving speed
A lawyer worries that listening to a "Commute" playlist in a mobile app makes users drive faster. As the DS: a) Define the population, unit of analysi...
Test a coefficient and explain t-distribution
In OLS, test whether feature j is relevant. a) State H0: β_j = 0 versus H1: β_j ≠ 0 and construct the t‑statistic t_j = b̂_j / se(b̂_j), giving the ex...
Narrow a confidence interval for a mean
You have a simple random sample with n = 100 and sample mean 100. The current 95% CI for the population mean is 100 ± 10, which a PM says is too wide....