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."
Analyze User Flags and Review Outcomes for Moderation Prioritization
UserFlags +---------------+--------------+----------+---------+ | User_FirstName| User_LastName| Video_ID | Flag_ID | +---------------+--------------+...
Analyze Factors Behind 20% Retail Revenue Decline
Retail Revenue Decline Analysis Scenario A retailer reports a 20% decline in revenue compared with a prior, comparable period. Assume revenue is net o...
Quality and frequency control for push notifications
Push Notifications: Quality, Overload Mitigation, and Per‑User Caps Context You are a data scientist working on push notifications for a consumer app....
Calculate Video Call Usage Metrics by Country and Date
video_calls +---------+-----------+------------+---------+----------+ | caller | recipient | ds | call_id | duration | +---------+-----------...
Single Queue vs Multiple Queues — Service Design
Bank Branch Queue Design: Single Line to c Tellers vs c Independent Lines Context and assumptions for comparability: - Arrivals are approximately Pois...
Implement Left Join Using Python Dictionaries Efficiently
Orders +---------+----------+--------+ | order_id| customer | amount | +---------+----------+--------+ | 101 | C1 | 250 | | 102 | ...
Analyze Impact of Customer Reviews on Sales Performance
Measuring the Impact of Product Reviews on Sales Context You are asked to propose how to quantify and causally estimate the impact of product review m...
Calculate 7-Day Rolling Average for Energy Consumption
Scenario Hiring manager wants a quick coding exercise to verify programming fluency. Question Write a Python function that takes a list of daily energ...
Find Maximum Sum of Contiguous Subarray Length k
Scenario Monitoring website traffic and needing the highest traffic within any fixed-length time window. Question Given an array of positive integers ...
Implement Infinite Fibonacci Generator Using Lazy Evaluation
Scenario Testing understanding of Python lazy evaluation and generators. Question Explain what lazy evaluation means in Python and implement a generat...
Calculate Weekly, Monthly Watch Hours for Paid Users
video_view_logs +---------+----------+----------------+------------+------------+ | user_id | video_id | watched_seconds| watch_date | device_type| +-...
Resolve Conflicting A/B Test Results in Cities
A/B Test Paradox Across Two Cities Scenario You ran an A/B test in two geographies (City X and City Y). Within each city, variant A outperforms varian...
Design Incremental Load Process for Large Relational Table
orders_daily_load +------------+-----------+-------------+--------+ | load_date | order_id | customer_id | amount | +------------+-----------+------...
Count, Return, Find, and Select in SQL Queries
orders +----------+--------------+------------+--------+ | order_id | customer_id | order_date | amount | +----------+--------------+------------+---...
Explore Dataset to Assess Quality and Choose Visualizations
Understanding a New Dataset: Profiling, Data Quality, and Visualization Plan Scenario You receive a new, unfamiliar dataset and must quickly generate ...
Determine Metrics for Group-Video Calling Experiment Success
Scenario You are the data scientist for a large consumer messaging app that currently supports 1:1 video calls. The product team is debating whether t...
Resolve Stakeholder Conflicts: Actions and Outcomes Explained
Behavioral & Leadership: Navigating Stakeholder Conflict (Data Scientist) Context You are a Data Scientist delivering a product/experiment with multip...
Identify Users with Specific Page Visit Sequence
page_visits +------------+---------+---------+----------+ | date | user_id | page_id | ts | +------------+---------+---------+----------+ ...
Implement Binary Search for Policy Violation Logs
violations +--------+---------+---------------+ | pin_id | type | violation_date| +--------+---------+---------------+ | 0 | spam | 2022-01...
Calculate Cumulative Sum for Each Integer in Table
numbers +-----+ | num | +-----+ | 1 | | 2 | | 13 | | 14 | | 15 | +-----+ Scenario You have a table containing one integer per row; for each row...