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."
Compute minimum sample size for A/B test
You are implementing a function to compute the minimum total sample size for an A/B test. You are given: - observed: a 1D array of historical/baseline...
Explain fraud types and evaluate a fraud model
You are interviewing for a Fraud Data Scientist role at PayPal. Answer the following: 1) List common fraud types relevant to payments (e.g., account t...
Design a CVR model for RTB bidding
Question You are a data scientist at a Demand-Side Platform (DSP) such as The Trade Desk, participating in Real-Time Bidding (RTB). For each ad opport...
Move zeros to the front
You are given an integer array nums. Reorder the array in place so that all 0 values are moved to the beginning of the array, while preserving the rel...
How should Uber evaluate lower ETA?
Uber wants to estimate the business value of reducing pickup ETA, where ETA refers to the rider-facing estimated time for a driver to arrive at the pi...
How to evaluate new listing notifications?
You work on an online marketplace. The product team wants to build a feature that notifies buyers when new products are listed that match their intere...
Design and assess a video-pin increase experiment
Question Pinterest wants to increase the share of video pins surfaced in the Home Feed (e.g., raising video share from a ~30% baseline toward a 45% ta...
Compute P(third Ace | Ace in first two)
Conditional probability with cards drawn without replacement Problem You draw three cards without replacement from a standard 52‑card deck (4 Aces). G...
Decide when CTR falls but revenue rises
Ads-Ranking A/B Test: Decision, Decomposition, Diagnostics, and Exec Readout Context You ran a user-level A/B test of a new ads-ranking model. The tre...
Create and query an e-commerce schema
PostgreSQL only. 1) Create these tables with appropriate types and constraints (choose minimal correct types): products(product_id PK, name NOT NULL, ...
Compute robust inference under skew and outliers
A/B test with skew, outliers, heteroskedasticity, missingness, and multiplicity You are comparing two independent product variants that produce a cont...
Compute partnership profit and break-even population
Co‑marketing Partnership Economics — 12‑Month Evaluation Setup - Issuer C1 earns 1% of a cardholder’s total card spending (interchange-like revenue). ...
Design rigorous A/B test and causal analysis
Experiment Design and Causal Inference: Multi-part Problem Context: You are designing a high-traffic web A/B test on a binary conversion metric. Answe...
Build ETA prediction and simulate impact
Predicting Delivery ETA (Minutes) Context You are given a take-home dataset with order-, store-, and dasher-level features. The goal is to predict del...
Compute violation rate and flag precision in SQL
You are analyzing a Trust & Safety product in BigQuery. Assume 'today' is 2025-09-01 (UTC). Define precise metrics and write SQL to compute them, bein...
Diagnose a 10% DAU drop
On-Call Incident: Yahoo Mail DAU Down 10% on 2025-09-01 Assume all times are UTC, the product is global, and DAU is the canonical daily active user me...
Prove and apply statistical ML fundamentals
Technical ML/Statistics Exercises (with precise math and small computations) Assume a standard supervised learning setting with n samples, p features,...
Design metrics and experiment for donation feature
Question Uber Eats is considering a new feature: when a user places an order, they can optionally add a donation (to the merchant or a merchant-select...
Calculate Jaccard Similarity Score for Two String Lists
Scenario During pair programming, the interviewer asks you to compare two lists of merchant tags and quantify their similarity. Question Implement a P...
Identify Key Metrics to Address Delivery Delays
Scenario DoorDash, a food-delivery marketplace, is seeing growing customer complaints about orders arriving late. You are the data scientist asked to ...