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."
Implement Jackknife and Random Choice
Write Python code for two implementation tasks without using np.random.choice directly: 1. Jackknife-style resampling. Given a one-dimensional collect...
How would you evaluate emoji reactions launch?
You work on a Messenger-like chat app (not Meta). The product team plans to ship a new feature: Emoji Reactions (a user can long-press a message for 5...
Write SQL for rankings, state, and aggregations
You are given several independent datasets. For each dataset, write the required SQL query (ANSI SQL is fine). Assume dates are in UTC and DATE column...
Investigating Correlation Between Ad Visits and Reports
Scenario You are on the analytics team at a large social media platform. A positive correlation has been observed between the number of page visits to...
Implement bootstrap mean and variance
You are given an array of N numeric observations x[0..N-1]. Write a function that uses bootstrap resampling to estimate: 1. the mean of the original s...
Compute probability at least one user uses feature
Problem Assume there are \(n\) users. Each user independently uses a certain feature with probability \(p\). 1) What is the probability that at least ...
Derive expected inversions and mean distribution
Random permutation inversion statistics Let π be a uniformly random permutation of length N. Let X be the number of inversions in π. 1. Compute the ex...
Find index with positive suffix sums
Given an unsorted integer array \(A\), find an index \(i\) such that every cumulative sum starting from \(i\) to the end of the array is strictly posi...
Evaluate new-product notification feature
A marketplace team is considering building a feature that notifies buyers when new products relevant to their interests are listed. How would you dete...
Design plant-infection algorithms
Consider an m x n grid where each cell contains one plant. Some plants are initially infected and all other plants are healthy. Time advances in whole...
Write the logistic regression loss function
Write the logistic regression loss function Logistic Regression Loss Consider binary logistic regression. - Dataset: \(\{(\mathbf{x}_i, y_i)\}_{i=1}^n...
Analyze document collaboration from CSV logs
You are given two CSV files exported from a document collaboration product. Data 1) doc_access.csv Each row represents a user accessing (viewing/editi...
Diagnose Job Application Decline: Funnel Analysis and Segmentation
Diagnose a Sharp Decline in Job Applications LinkedIn sees a sudden, sharp decline in its Job Application metric, defined broadly as completed job app...
Estimate Causal Impact Using Synthetic Control Methods
Estimate Causal Impact Using Synthetic Control Methods A product feature has already launched to 100% of traffic, and no explicit control or holdout g...
Diagnosing a drop in total ads revenue
Diagnosing a Sharp Drop in Global Ads Revenue You are a data scientist supporting a large ads marketplace. Last week, global ads revenue declined shar...
Diagnose Causes and Test Hypotheses for Metric Drop
Diagnosing and Testing a Sudden Metric Drop A large consumer web or mobile product sees its key business metric drop materially and suddenly. Assume s...
Calculate Profitability with Different Pricing Schemes
Unit Economics and Break-even Analysis You are evaluating a subscription product's monthly unit economics. Unless otherwise noted, fixed cost is $400 ...
Construct a Churn-Prediction Pipeline Using Scikit-Learn
Construct a Churn-Prediction Pipeline in scikit-learn Scenario You are a data scientist on a subscription business. You need to build a model that pre...
Optimize Credit-Card Strategy: Pricing, Limits, and Target Segments
Credit-Card Business Optimization Case You are evaluating a new credit-card product. You have or will estimate per-segment cost, revenue, and risk inp...
Determine Appropriate Statistical Test for Comparing Means
Statistical Test for Comparing Mean Active Minutes You have two weeks of experiment data for a new algorithm. The primary metric is user active minute...