Data Scientist Interview Questions
Practice the exact questions companies are asking right now.
"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."
How would you evaluate stolen-post detection?
You are interviewing for a Meta DSA (product analytics / data science) role. The product team is launching a new Stolen Post Detection algorithm that ...
Design robber detection from surveillance video
You’re a Data Scientist on a team building a computer-vision system for public-safety monitoring. Problem Design an ML system that uses fixed surveill...
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 reply-based recipient metrics
You work on a social product and are given two tables. Assumptions (use these unless you state otherwise): - All timestamps are in UTC. - A “reply” is...
Solve two string DP/hash problems
Solve the following two coding questions. 1) Unique Morse Code Transformations You are given an array of strings words (lowercase English letters). Us...
How to evaluate similar-listing notifications feature
Case study (Marketplace product analytics) Context: Circle is a US marketplace app for buying and selling second‑hand products. On a product listing p...
Estimate ATE of personalization on streaming
You are given a user-level dataset from an online experiment that randomized personalization (treatment) vs no personalization (control). Assume one r...
Answer Amazon-style behavioral questions
You are interviewing for a role at Amazon and are asked the following behavioral questions. Answer each using the STAR method (Situation, Task, Action...
Compute probability an account is fake
A platform uses an automated classifier to flag potentially fake accounts. Assume: - Base rate: 2% of accounts are fake. - The classifier flags a fake...
Explain why the t-statistic helps
Suppose you estimate an effect size \(\hat{\beta}\) in a regression model or an A/B test and compute a standard error \(SE(\hat{\beta})\). Explain why...
Answer core probability and statistics questions
Answer the following interview-style probability/statistics questions. Provide formulas and short explanations. 1) Bayes’ rule: State Bayes’ rule. Giv...
Debug and fix a PyTorch Transformer training loop
Minimal Causal LM Debugging and Optimization Context You are given a tiny causal decoder-only language model implemented in PyTorch. It appears to "tr...
Find missing numbers in sequences
You are given several number sequences (integers and/or rational numbers). Each sequence contains exactly one missing term written as ?. For each sequ...
Evaluate piecewise linear function at x
You are given a polyline defined by n 2D points \((x_i, y_i)\). Connecting consecutive points with straight line segments forms a piecewise linear fun...
Count Recent High-Volume Call Users
Given the following tables: users - user_id BIGINT - country STRING - is_active BOOLEAN calls - call_id BIGINT - initiated_at TIMESTAMP - caller_id BI...
How to measure harmful-content severity and run experiments
Context You are a Data Scientist on a social media platform working on harmful content (e.g., hate/harassment, self-harm, violence, sexual exploitatio...
How predict vehicles’ turn direction at intersection?
At an intersection, there are N vehicles stopped or moving slowly. For each vehicle you have historical time-series data up to the current time: - Pos...
Compute ads revenue by geography in SQL
You have ad delivery logs for a shop-ads system. Tables ad_impressions - impression_id STRING (PK) - ts TIMESTAMP (UTC) - user_id STRING - shop_id STR...
Compute ITT, TOT, and LATE with noncompliance
In the same personalization experiment, not everyone assigned to treatment actually receives personalization (noncompliance). You are given user-level...
How would you define and use retention metrics?
Scenario You are a Data Scientist supporting a consumer product (app or website). A PM asks you to “dive deep” on user retention and recommends tracki...