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."
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"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
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"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."
Review Preprocessing Code and Tests
You are reviewing a small Python preprocessing codebase during an interview. You do not need to write code. Part A: Environment and execution A shell ...
Design Identity-Trust A/B Test
You are interviewing for a Data Scientist role on an Identity & Trust team at a consumer product company. The team wants to launch a feature that stre...
Calculate a Confidence Interval
Suppose an online experiment compares treatment and control on conversion rate. Treatment has x1 conversions out of n1 users, and control has x0 conve...
How to target commute coupon users?
You are a Data Scientist on the commute team at a ride-sharing company such as Lyft. The team wants to launch a coupon campaign to increase usage of c...
How would you evaluate a free-trial A/B test?
You run an online marketing experiment to evaluate whether offering a free 1‑month trial increases growth. Experiment context - Eligible visitors are ...
Handle multicollinearity in feature selection
You are building an interpretable predictive model for an insurance company, such as a linear or logistic regression model for claim risk. Several inp...
Count inversions in a permutation
Problem Given an array a of length n that is a permutation of distinct integers (e.g., 1..n), define an inversion as a pair of indices (i, j) such tha...
Design experiments for marketplace balance
You propose a new supplier prioritization (ranking) policy intended to increase order completion in a two-sided marketplace with known interference be...
Design robust primary and guardrail metrics
Experiment Metric Design, Guardrails, and Power for a 14-Day A/B Test Context You are testing a newly launched, guest-facing booking feature in a glob...
Choose fastest way to transfer 2 TB
You need to transfer a 2 TB dataset to someone located in San Francisco as fast as possible. - What transfer method(s) would you choose and why? - St...
Investigate marketplace metrics and experiment rollout
You are interviewing for a Senior Data Scientist role at a two-sided marketplace like Instacart, where customers place delivery orders and shoppers ch...
Query US-based users and most active forums
You are given user and post data for an online forum platform. Tables (schemas) Assume the following tables: users - user_id BIGINT (PK) - home_countr...
Compute DiD and validate parallel trends
You are given observational/experiment-like panel data as three equal-length arrays: - period[i]: an integer time period label for observation i (e.g....
How should you renew or replace a show?
You are a data scientist at a streaming company similar to Netflix or Hulu. Your team helps decide whether existing series should be renewed or cancel...
Deep dive a technical project and its impact
Describe one technical project you led or significantly contributed to (DS/analytics/ML/engineering). The interviewer wants both a high-level story an...
Measure Billboard Campaign Impact: Design, Bias, Test Strategy
Measuring Billboard Impact on Brand Awareness Scenario A marketing team launched billboard ads in several cities and wants to estimate the campaign's ...
Implement Connect Four Winner Detection
Implement a Connect Four-style game engine. The board has 6 rows and 7 columns. Two players alternate turns. On each turn, the current player chooses ...
How to diagnose traffic and measure relevance?
You are a data scientist at LinkedIn evaluating two separate Home-page product questions. 1. Home Page to Profile Page traffic declined. The tracked m...
Calculate Conversion Lift CI
In an A/B test, the control group had 1,000 users and 120 conversions. The treatment group had 1,000 users and 150 conversions. Using a normal approxi...
Compute join counts and window ranks
Given the following small schema and data, answer all parts precisely and justify each count/output. Tables and rows: Customers(cust_id INT PRIMARY KE...