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."
Define and compute shop visibility in SQL
You own the 'shop visibility' KPI for a marketplace. Define a precise metric and write SQL to compute it over the last 7 days (use today = 2025-09-01,...
Compute p-values, power, and adjust errors
Statistics Interview Task (Onsite) You are evaluating a product experiment and related analytics questions. Answer precisely, showing calculations and...
Write mini-batch gradient descent
Implement a generic mini-batch gradient descent routine: inputs are differentiable loss L(θ; x), initial θ0, batch size b, steps T, and learning-rate ...
Explain SVM kernels and complexity
Support Vector Machines – Core Concepts and Practice You are interviewing for a Data Scientist role. Answer the following about Support Vector Machine...
Tune metrics for imbalanced classification
Fraud Detection With Rare Positives (0.5%) and Messy Data You are designing a supervised transaction-level fraud detector. Positives (fraud) are rare ...
Diagnose and fix linear regression violations
Given a linear model y = Xβ + ε on 10,000 observations: (a) State all Gauss–Markov assumptions and which are needed for BLUE vs inference. (b) Show wh...
Compute p-values and adjust multiplicity
You test if a coin is fair after 20 flips and observe 17 heads. (a) Compute the exact two-sided p-value under a Binomial(20, 0.5) model. (b) Approxima...
Apply Bayes theorem with conjugate priors
A website’s true daily purchase conversion p is unknown. Prior: p ~ Beta(2, 8). Day 1: 10 purchases out of 120 visits; Day 2: 18 purchases out of 150 ...
Detect sequence rule and repair anomaly
Implement next_value(seq: list[int]) that detects the rule of a numeric sequence and returns a tuple (model_name, parameters, anomaly_index_or_None, n...
Minimize max L1 radius with k centers in 1D
You are given an array A of n integers (values may be negative and may repeat) and an integer k (1 ≤ k ≤ n). Place k cluster centers anywhere on the r...
Increase posts receiving one comment
Goal: Increase the share of group posts that receive ≥1 comment within 48 hours. Assume today is 2025-09-01. (a) Precisely define the primary metric a...
Set the Group Call participant cap
We must set a maximum participants cap K for Group Calls. You have telemetry at the call level: calls(call_id, start_ts, participants_count, video_on_...
Optimize bread-factory pipeline for max profit
You can assemble a production line by choosing modules of three types: Mixers, Ovens, Packers. Each module i has (type, build_cost_i, throughput_i uni...
Reflect on feedback and metric trade-offs
Describe a time you chose a simpler metric under tight time constraints and later received critical feedback that it was oversimplified (e.g., from a ...
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...
Diagnose rising account switching and falling actives
Diagnostic Plan: Account Switching Up, Active Users Down Context You observed a sudden pattern: the number of users switching accounts increased, whil...
Design an A/B test for pinned-unread feature
Experiment Design: Evaluating a Pinned-Unread Chat Feature Context You are evaluating a new messaging feature that pins chats with unread messages to ...
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...
Build and evaluate airline delay prediction model
You are given several CSVs for the classic airline delay challenge with columns like flight_date, carrier, flight_num, origin, dest, sched_dep, sched_...
Decide event notification launch via experiments
Meta plans a new notification that tells you when friends are going to an event. Determine whether to launch it. 1) Design the experiment accounting f...