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."
Count subarrays equal to target
Count subarrays equal to target Given an integer array nums and an integer k, count the number of contiguous subarrays whose sum equals k. Solve it in...
Find longest substring with at least k repeats
Find longest substring with at least k repeats Longest substring where each character appears at least k times You are given: - a string s consisting ...
Compute window averages and merge intervals
Compute window averages and merge intervals You are given two independent pandas tasks. 1. Centered sliding-window average - Input DataFrame df with c...
How would you choose a classification threshold?
You trained a binary classifier that outputs a probability score p(y=1|x). You must choose a decision threshold t to convert probabilities into class ...
Build and iteratively improve sentiment classifier
You need to build a sentiment classification model (e.g., positive/neutral/negative) for user-generated text. You already shipped an initial version, ...
Design human review to estimate model accuracy
Design human review to estimate model accuracy You need to estimate the accuracy of an ML classifier on a population of subjects. You can only afford ...
Design an A/B Test for Homepage Layout Impact
Design an A/B Test for Homepage Layout Impact Experiment Design: New Homepage Layout → Purchase Rate Context You are designing an A/B test to evaluate...
Examine Data to Boost Instagram Purchases Effectively
Examine Data to Boost Instagram Purchases Effectively Increasing Instagram In‑App Purchases: Data, Experiments, and Trade‑off Decisions Scenario You a...
Describe Your Most Challenging Project and Its Outcome
Describe Your Most Challenging Project and Its Outcome Tell me about the most challenging project, situation, or thing you have worked on as a data sc...
Explain Key Terms in Model Evaluation for Fraud Detection
Explain Key Terms in Model Evaluation for Fraud Detection Model Evaluation Terminology and Business Trade-offs Scenario Phone screen focused on unders...
Determine Optimal Budget Allocation for Maximum Profit
Determine Optimal Budget Allocation for Maximum Profit Scenario You have three user-acquisition platforms: Live Phone Calls, Social Media Ads, and Ema...
Influence Stakeholders Using Data: Handle Conflicts, Measure Success
Influence Stakeholders Using Data: Handle Conflicts, Measure Success Behavioral & Leadership Question (Onsite) Scenario Job-fit conversation with seni...
Describe Handling Unexpected Feedback and Actions Taken
Describe Handling Unexpected Feedback and Actions Taken Behavioral: Resilience After Unexpected Negative Feedback or Rejection Context You are in an o...
Calculate Probability of Heads in Coin Flip Experiment
Calculate Probability of Heads in Coin Flip Experiment Coin Flips: Counting and Binomial Probabilities Context Assume 10 independent flips of a fair c...
Determine Sample Size for Promotion Campaign A/B Test
Determine Sample Size for Promotion Campaign A/B Test Scenario Uber plans to launch a promotion campaign and wants to evaluate its effectiveness with ...
Evaluate Instagram Shopping Tab Success with Key Metrics
Evaluate Instagram Shopping Tab Success with Key Metrics Instagram Shopping Tab: Post-Launch Evaluation and Sizing Context You are evaluating the succ...
Implement Python Function for Longest Unique Substring Length
Scenario Real-time text analytics service enforcing uniqueness constraints Question Implement a Python function returning the length of the longest su...
Estimate Super Bowl QR Code Scan Rate Using Historical Data
Estimate Super Bowl QR Code Scan Rate Using Historical Data Estimating QR Scan and Sign-up Conversion for a Super Bowl TV Ad Scenario A Super Bowl TV ...
Implement and Analyze 'Merge k Sorted Lists' Algorithm
Scenario Algorithm coding challenge during the final interview round. Question Implement LeetCode 23 ‘Merge k Sorted Lists’ and explain your complexit...
Investigate Anomalies in Coinbase Wallet Engagement Metrics
Investigate Anomalies in Coinbase Wallet Engagement Metrics Coinbase Wallet: Anomaly Investigation Framing Context You observe an unexpected spike or ...