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."
Use Bayes to interpret a broken radar alarm
A “radar” system (or anomaly alarm) is suspected to be unreliable. You are asked to interpret its alerts and recommend how to operate it. Given Define...
Compute posterior for biased coin after 3H1T
You are given a coin known to be biased: one face lands with probability 2/3 and the other with probability 1/3, but you do not know whether Heads is ...
Solve probability and expectation problems
You are asked to solve the following probability and mathematical interview problems: 1. Squid Game glass bridge: There are B sequential bridge steps....
Build cold-start restaurant ratings
Uber Eats wants a cold-start rating system for newly onboarded restaurants before they accumulate enough real reviews. You are asked to design the mod...
Design evaluation when A/B test is impossible
Scenario You want to evaluate whether a product or model change (e.g., a new ranking strategy, pricing rule, or UI change) improves business outcomes....
How would you critique this regression?
Question You are reviewing a modeling workflow built by another data scientist and asked to critique it. Business context A website receives traffic f...
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...
Implement stacks, streaming median, and upward path sum
Complete the following coding problems. State the time/space complexity and key edge cases for each. 1) MinStack Design a stack that supports: - push(...
How do you diagnose a ratio metric change
In an A/B test, the treatment group shows a statistically significant increase in a ratio metric: - CTR = clicks / impressions increased by +1.2% rela...
Evaluate launching a vegan burger
Scenario You run a fast-food burger chain, and a rival has just launched a hit vegan burger. The question on the table: should you add a vegan burger ...
Investigate Falling Brand-Ad Spend
On a video ads platform, there are two ad products: - Direct Ads: optimized for immediate response. - Brand Ads: when a user clicks the video ad, they...
Calculate Order Request Metrics
You are working with DoorDash order and delivery-request data. Write SQL to answer the questions below. Tables: 1. orders - order_id BIGINT, primary k...
Design Product Notification and Autocomplete Experiments
You are interviewing for a Product Data Scientist role at Discord. Answer both product experimentation case studies below. Case 1: Subscription notifi...
Assess Adding Bicycle Dashers
DoorDash is considering allowing bicycle couriers (bike dashers) to fulfill deliveries in a city that is currently served mostly by car/scooter dasher...
Design and analyze a switchback experiment
Design and Analyze a Switchback Experiment: Reducing Cold-Food Incidents for Bike Couriers You are a data scientist on a delivery-marketplace team. A ...
How do you compute expected return for two projects?
Case: A TV studio's project & divestiture decisions under uncertainty You are the CEO of a media/streaming company. You run an existing TV show, "Anal...
Design Testing Without A/B Experiments
Suppose a product team wants to evaluate a new feature that is intended to improve user engagement and long-term retention, but a clean randomized A/B...
Find top-paid employee per department
Tables Assume the company stores employee compensation by department assignment. employee_dept_salary - employee_id INT - employee_name VARCHAR - depa...
Design multimodal deployment under compute limits
You need to answer a set of questions related to multimodal model deployment and post-training optimization in an interview. Provide systematic explan...
Compute C/T metrics from bookings and visits
Given two tables, compute control vs treatment (C/T) metrics, apply 24‑hour attribution, and generate a daily plot. Treat “today” as 2025‑09‑01; use t...