Amazon Data Scientist Interview Questions
Amazon Data Scientist interview questions are famously comprehensive because Amazon evaluates both technical depth and Amazonian fit. Expect a mix of SQL and Python problems, statistics and experiment-design questions, machine‑learning discussion, and behavioral probes tied to Amazon’s Leadership Principles. Interviews typically include an initial recruiter screen, one or two technical phone screens, and a loop of 4–6 on‑site/virtual interviews where each 45–60 minute slot focuses on a different competency. Interviewers look for clear problem decomposition, metric-driven thinking, defensible trade‑offs, and the ability to translate analysis into business impact. For effective interview preparation, build a structured plan: craft concise STAR stories mapped to Leadership Principles with quantified outcomes, drill SQL (joins, window functions, CTEs, performance), refresh statistics and A/B testing fundamentals, and sharpen Python/data-manipulation skills. Practice explaining assumptions, communicating results for technical and non‑technical audiences, and walking through model choices and evaluation metrics. Mock interviews and timed problem sets that simulate the loop rhythm are especially valuable to convert knowledge into polished, confident answers.

"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."
"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."
Retrieve First Active and Last Inactive Dates per User
Given a table activity that tracks user activities, write a SQL query to retrieve the first active date and last inactive date for each user. Table Sc...
Implement a high-throughput web crawler safely
Design and code (pseudocode acceptable) a multi-threaded web crawler that favors breadth-first discovery while continuously running analysis tasks on ...
Select Top Customers Using Transaction Data Filters
transactions +----+---------+------------+--------+ | id | user_id | order_date | amount | +----+---------+------------+--------+ | 1 | 101 | 202...
Analyze an A/B test over last 7 days
A/B Test Readout and Decision (2025-08-26 to 2025-09-01) Context A 50/50 A/B experiment on the checkout flow ran for 7 days, from 2025-08-26 through 2...
Solve two-sum variants at scale
Base task: Given nums = [3, 1, 2, 2, 4] and target = 4, return the 0-based index pair (i, j) with i < j such that nums[i] + nums[j] = target. If multi...
Diagnose and fix underperforming ML model
Rapidly Improving Recall Under Class Imbalance (One-Day Plan) Context You inherit a binary fraud detection model with severe class imbalance (positive...
Implement streaming k-way merge with constraints
Implement a function merge_k(iterators, N) that returns the first N items of the global ascending order from k sorted, potentially unbounded iterators...
Design causal study for reminder impact
Observational Causal Study: Reminder Program With Staggered Market × Channel Launch Context You are evaluating the causal impact of medication-subscri...
Describe a time you solved a complex problem
Behavioral (Leadership/Ownership): Describe a time when you solved a complex problem by digging into details. In your answer, cover: - The context and...
Choose regularization norms and model formulations
Regularization and model choice. 1) For linear and logistic regression, write the objective functions with L0, L1, L2, and L-infinity penalties in bot...
Process real-time enter/exit events and actives
You receive a real-time stream of events with schema: user_id (str), channel (str), event_type ("enter"|"exit"), ts (UTC ISO timestamp). A user can ‘e...
Find recommended friend pairs by shared listening
Problem (SQL) You work on a music app and want to recommend new friend connections based on listening similarity. Tables Assume the following schemas:...
Implement robust word counts and min/max
You receive a 50GB UTF-8 text corpus on disk. Implement a Python solution that:\n- Streams the file without loading it fully into memory.\n- Counts ca...
Prioritize a new warehouse proposal with data
Build vs. Lease vs. Defer: New Fulfillment Center Decision Context You are evaluating whether to open a new fulfillment center (FC) to improve deliver...
Optimize precision–recall under class imbalance
You have extreme class imbalance (positive rate ~1%). You score 12 examples as follows (id, true_label, score): A,1,0.92; B,0,0.90; C,0,0.88; D,0,0.70...
How to evaluate adding video ads in a game
Case study: Evaluate adding video ads to a mobile game You are the Data Scientist for a free-to-play mobile game. The product team wants to add video ...
Profile and visualize an unfamiliar dataset
Task: Quickly Understand an Undocumented Events+Purchases CSV and Produce Executive-Ready Visuals Context You are handed a single CSV that mixes user ...
Plan and analyze an A/B test
A/B Test: Power, Clustering, Sequential Monitoring, Multiple Comparisons, and Diagnostics Context You are planning an A/B test for a dashboard change ...
Compute p-values, CIs, and adjust multiples
Hypothesis testing and intervals in practice. Part A (z vs t): You sample n = 15 observations from a population with unknown variance and observe samp...
Compare Random Forests vs Gradient Boosting rigorously
Technical ML Choice: Random Forest vs. Gradient-Boosted Trees for Large-Scale Binary Classification Problem Setup You need to choose between a Random ...