Data Scientist Interview Questions
Practice 2,956 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."
Find top countries by population per continent
Table world_population - continent VARCHAR - country VARCHAR - population BIGINT Assume each row is a country’s latest population and (continent, coun...
Do US members upload more videos than non-US?
You suspect video posting adoption differs between US and international members. Tables members - memberid INT (PK) - country VARCHAR (e.g., 'usa', '...
Move zeros to the front
Given an integer array nums, move all elements equal to 0 to the beginning of the array while preserving the relative order of all non-zero elements. ...
Implement merge sort and largest 1-rectangle
The coding round included two algorithm questions: 1. Implement merge sort for an array of integers. Return the sorted array and explain its time and ...
Compute statistics in data stream
Question Design a data structure that supports computing the current max, mean, and mode for an unbounded integer data stream. Estimate the memory usa...
Solve Algorithmic Challenges in Online Coding Assessments
Scenario Online assessment requiring implementation of common algorithmic problems. Question Given an array of integers and a target, return indices o...
Explain PCA and L2 Normalization in Machine Learning
Scenario Experian DataLabs Data Scientist technical screen — a machine-learning deep-dive on the modelling choices used in your project, mixed with co...
Identify Pirate Themes Using Similarity Score Algorithm
Scenario Engineering wants an automated way to spot custom themes that are probably just pirate themes in disguise. Question Write Python that takes t...
Calculate Break-Even Point and Profit Impact Analysis
Break-even and Profit Sensitivity for a Restaurant Context A restaurant has fixed monthly costs (rent, salaries) and a variable cost per customer (foo...
Calculate Break-even for New Credit Card Product Launch
Break-Even for a Credit Card with Annual Fee, Interchange, and Cashback Context You are evaluating a new credit-card product. Revenue comes from: - An...
Investigate Why DAU Stagnates Despite High Downloads
Investigating High Daily Downloads but Flat DAU Scenario Adobe Express reports approximately 1M daily downloads, yet daily active users (DAU) remain f...
Design a house-price prediction model
Problem You are asked to build a model to predict house sale prices for a city of your choice. Data (assume typical real-estate fields) You have a his...
Match readings with latest same-city humidity
Problem You are given two time-sorted lists of sensor readings: - Temperature records: (time, city, reading) - Humidity records: (time, city, reading)...
Answer four core statistics questions
Problem set (timed) Answer the following four questions. 1) Covariance of order statistics Let \(X\) and \(Y\) be independent \(\mathrm{Unif}(0,1)\). ...
Add two integer strings using digit-adder
Coding Prompt You are given a helper function: - addDigits(a, b) -> (sumDigit, carry) - a and b are single decimal digits (characters '0'…'9' or int...
Return all combinations that sum to target
Given an array of distinct positive integers candidates and an integer target, return all unique combinations of candidates where the chosen numbers s...
How would you test swapping two CTA buttons?
You work on the Airwallex marketing/product landing page. There are two primary CTA buttons: - “See a demo” - “Get started” A proposal suggests swappi...
Build and evaluate donation propensity model
You need a model to maximize expected net revenue from solicitations. Costs: online reach costs $1 per person; gala attendance costs $100 per attendee...
Find top category per region in Aug 2025
You are given the following schema and sample data. Schema: - customers(customer_id INT, name TEXT, region TEXT) - orders(order_id INT, customer_id IN...
Compute join counts and window ranks
Given the following small schema and data, answer all parts precisely and justify each count/output. Tables and rows: Customers(cust_id INT PRIMARY KE...