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."
Estimate Portal’s causal lift on video-call usage
Define and estimate the causal effect of purchasing a Meta Portal on users’ video‑calling behavior. Today is 2025-09-01, and only a small fraction pur...
Measure a friend-recommendation launch
A new friend-recommendation algorithm ships behind a feature flag. Design how you will measure success and decide whether to launch: - State no more t...
Differentiate fixed and variable costs with examples
Unit Economics: Fixed vs. Variable Costs in a Subscription Streaming Business Task - Define fixed cost vs. variable cost for a subscription streaming ...
Optimize amusement park pricing, capacity, and testing
Context You are interviewing for a Data Scientist role focused on analytics and experimentation. An amusement park is considering launching a paid Fas...
Describe handling an urgent ad-hoc request
Behavioral Prompt: Urgent, Unscheduled Analytics Request (STAR) You are interviewing for a Data Scientist role and are asked to provide a STAR-formatt...
Compute precision under noisy annotators
Two-Annotator Labeling Policy: Precision, Recall, F1, and Generalization You have two independent annotators who review videos and label them as "ille...
Design pricing and multivariate button experiments
You join a B2B SaaS firm with three public tiers (Basic $25/month, Pro $50/month, Enterprise = sales-quoted). The PM asks for a 2‑week A/B test to rai...
Design metrics and an A/B test for an app
Pick a consumer digital app you love. Assume the interviewer knows nothing about it. 1) Explain the product, core jobs-to-be-done, target audience seg...
Define and sample a truncated normal
Define the truncated normal Z | a < Z < b for Z ~ N(0,1): write the normalized pdf and cdf. Then design efficient samplers for three cases: (i) a = 1,...
Justify and harden your analytics and BI stack
List your current analytics tech suite end-to-end (ingestion, storage/warehouse, transformation, orchestration, catalog/lineage, experimentation platf...
Find daily first-order merchants with SQL
Given the table below, write a single SQL query using window functions to: A) For each calendar date (UTC), return all merchant_id(s) whose order is t...
Diagnose and fix underperforming ML model
Rapidly Improving Recall Under Class Imbalance (One-Day Plan) Context You inherit a binary fraud detection model with severe class imbalance (positive...
Compute robust linear interpolation with edge cases
You are given two distinct points (x0, y0) and (x1, y1) with x0 != x1. a) Derive the linear interpolation function f(x) on [min(x0, x1), max(x0, x1)] ...
Describe cross-functional collaboration under time pressure
Tell me about a time you led a cross-functional initiative with ambiguous requirements and severe time pressure. The interviewer asked generic or shif...
Reduce variance with covariate adjustment
Experiment Design and CUPED/Regression Adjustment You are running a randomized A/B test with outcome Y. You also have a pre-period covariate X (measur...
Apply sequential testing without p-hacking
Sequential Monitoring With Early Stopping Context: You are planning a two‑sided hypothesis test with continuous monitoring and early stopping for effi...
Detect and address Simpson’s paradox
Experiment Aggregation Bias and Heterogeneity: Simpson's Paradox, Robust Estimation, and Decisioning Context You ran a randomized experiment measuring...
Estimate OLS via streaming sufficient statistics
Streaming OLS and Ridge for Out-of-Core, High-Dimensional Linear Regression You need to estimate linear regression coefficients when the dataset is to...
Design and analyze A/B test with interference
You must ship a News Feed ranking change where content produced by treated users can be seen by control users, creating interference and within-user c...
Contrast OLS, DiD, and PSM assumptions
For the shuttle impact problem, contrast OLS, DiD, and PSM rigorously. Do the following: 1) write the OLS and two-way fixed-effects DiD regression equ...