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."
Compare two rare-event detection models statistically
You are evaluating two models (Model A and Model B) for rare-event detection (e.g., fraud, abuse, medical adverse event). Positives are extremely rare...
Write SQL for lowest price with ratings
You have two tables. Schema: - products(product_id INT PRIMARY KEY, product_name TEXT, category TEXT) - purchase(purchase_id INT PRIMARY KEY, product_...
Design a network-aware Wi‑Fi badge experiment
You work on a two‑sided travel search marketplace and product wants to add a “High Wi‑Fi” badge/filter in the search bar to help remote workers. Recom...
Design and analyze a free-trial A/B test
A/B Test Design: 1‑Month Free Trial Impact on Paid Subscription Conversion You are evaluating whether offering a 1‑month free trial increases paid sub...
How would you test a price increase?
You are a data scientist at a B2C AI video editing software company (subscription-based, with a free trial and paid tiers). Product leadership is cons...
Solve a Skyscraper puzzle efficiently
Design and implement a solver for the Skyscraper logic puzzle on an $N \times N$ grid, where $3 \le N \le 7$. The board is a grid of building heights....
Find maximum follow depth using recursion
You are given a directed follows relationship representing a social graph: - Each record (follower_id, followee_id) means follower_id follows followee...
Design and Evaluate a Home Carousel
Pinterest is considering adding a horizontally scrollable carousel at the top of the Home feed, similar to Instagram Stories. The carousel may surface...
Compute Minimum Parentheses Additions
Given a string s consisting only of the characters '(' and ')', compute the minimum number of parentheses that must be inserted anywhere in the string...
Design a Low-Latency Store Recommender
You are designing the home-page store recommendation system for a food delivery app such as DoorDash. A request contains very little context: primaril...
Compute credit-card portfolio profit and breakeven
A bank is evaluating a new credit card. Segments: A: 30,000 customers, capture rate 20%, avg annual spend per captured customer = $100,000. B: any pop...
How should you evaluate unconnected content?
A social media platform has launched a feed feature that increases the share of unconnected content, meaning posts from creators who do not have an ex...
Implement Factorial and Squares
Question In a live coding interview, write two Python functions and be ready to discuss their behavior. 1. factorial(n): Given a non-negative integer ...
How to measure harmful-content severity and run experiments
Question You are a Data Scientist working on content integrity / harmful content at a large social media platform (e.g., hate/harassment, self-harm, g...
Build House Price Model Responsibly
You are asked two machine-learning questions. Part A: House-price prediction Using a cleaned housing dataset with target sale_price, describe an end-t...
How would you investigate a metric decline?
Scenario You are a Data Scientist supporting a consumer marketplace product. A key business metric (e.g., orders/day, conversion rate, revenue, profit...
How to debug an apparent D14 retention drop
Scenario A dashboard shows D14 retention (users retained on day 14 after signup/first activity). In the last week, the chart shows a sharp decline. As...
Calculate annual percentages and YoY by cohorts
Answer both SQL and Python parts. Be precise about deduping and denominator choices. SQL schema (sample rows): orders order_id | user_id | order_date ...
Design a target‑user prediction system
Predicting 30‑Day Adoption of Product P for Budgeted Outreach Context You are tasked with building a model to prioritize user outreach for Product P. ...
Describe influencing without authority
Behavioral (STAR) Prompt: Disagreeing With a Senior Engineer's Design Without Authority Context You are interviewing for a Data Scientist role in an o...