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."
Detect and address multicollinearity
Prompt You fit a linear/logistic regression model and suspect multicollinearity among features. 1. What is multicollinearity and why is it a problem? ...
Explain decision trees and tree ensembles
Prompt 1. Explain how a decision tree works for classification or regression. 2. How does the tree choose a split (objective functions for classificat...
Compute p-values for 2 variants vs control
A/B/n test: compute p-values and make a ship decision You ran an online A/B/n experiment with 1 control and 2 treatment variants (A/B/C). You are give...
Build next-word predictor with O(1) lookup
Problem You are given a training corpus where each training example is a tokenized sentence (array of words). Example training sentences: - ["I", "am"...
How would you compare Facebook vs Instagram Stories?
You work on short-form ephemeral content. Both Facebook Stories and Instagram Stories exist, and leadership asks: Which product should we invest in, a...
Implement np.random.choice
Implement a function similar to numpy.random.choice. Function signature choice(a, size=None, replace=True, p=None) -> samples Requirements - a can be:...
Write SQL to compute max and min marks
Tables marks | column | type | notes | |---|---|---| | student_id | INT | primary key | | marks | INT | not null | Task Write a SQL query that returns...
Design regression and classification ML pipelines
Take‑Home: Two End‑to‑End ML Workflows on Tabular Data Objective Design and implement two complete machine learning workflows on tabular data (typical...
Explain motivations and background for hedge fund role
Behavioral HR Screen: Data Scientist at a Hedge Fund (RCM) Prompt Give a concise self-introduction, then cover the following: 1. Academic background, ...
Minimize moves to transform floor layouts
You are given an initial arrangement of apartments across Floors 1–4 and a target arrangement. In one move you may reposition a single apartment to a ...
Describe leadership and collaboration examples
For a Meta Data Scientist, Product Analytics interview, answer the following behavioral questions using concrete examples. For each one, explain the b...
Write monthly customer and sales SQL queries
You are analyzing a food-delivery marketplace. Tables Assume the following schema (you may add minor helper CTEs as needed): orders - order_id (BIGINT...
Infer posterior after losing pick
Conditional probability after observing a loss You have three cats in a jumping contest: - Cat 1 (most athletic) wins with probability p1 - Cat 2 (mid...
Convert number words to integer
Given a line containing an English phrase representing a number in the range −999,999,999 to 999,999,999, convert it to its integer value. Supported w...
Analyze document collaboration patterns
You are given two CSV files and asked to analyze collaboration behavior on documents. File 1: document_activity.csv Each row is a document view event....
How to design Shop ad ranking
Suppose the experiment suggests that increasing exposure for Shop ads may be beneficial. The interviewer then asks how you would design the ranking al...
Check if a numeric string is divisible by 8
Question You are given a very large non-negative integer represented as a decimal string s (it may be too large to fit in standard 64-bit integer type...
Implement Fibonacci with efficiency constraints
Write a function fib(n) that returns the nth Fibonacci number (0-indexed: fib(0)=0, fib(1)=1). Requirements: - Handle n up to at least 10^6. - Discuss...
How do you expand nested placeholders in strings?
You are given a dictionary of string templates. Keys are identifiers like X, Y, Z. A template may contain placeholders of the form %KEY%, which should...
Calculate Expected Users Linking Coinbase Wallets
Scenario When users sign up for Coinbase, each of the n users is independently prompted to link a crypto wallet. Each user links their wallet with pro...