Tech Interview Questions

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9.0k Questions 486 Companies08.11.2026
Showing 20 results
Role
Meta logo
Meta
Medium
Data Scientist Locked

Build a Bayes classifier for reviewer types

This question evaluates Bayesian inference skills, including posterior updating under conditional independence, likelihood modeling for categorical ob...

Machine Learning
2
0
25 people solved
Oct 13, 2025
Capital One logo
Capital One
Medium
Data Scientist

Impute, join, and upsert using SQL and Python

Write both SQL and Python (pandas) to complete the following data-manipulation tasks. Assume today is 2025-09-01 for any time filters. Schema: custome...

Data Manipulation (SQL/Python)
1
0
9 people solved
Oct 13, 2025
Capital One logo
Capital One
Easy
Data Scientist Locked

Find premium share for break-even

This question evaluates a candidate's ability to construct and manipulate a linear financial model and perform break-even analysis using algebra, basi...

Statistics & Math
1
0
35 people solved
Oct 13, 2025
Capital One logo
Capital One
Medium
Data Scientist Locked

Design profitability growth plan

This question evaluates a data scientist's skills in business analytics, experimentation design, and strategic framework development for profitability...

Analytics & Experimentation
3
0
39 people solved
Oct 13, 2025
Meta logo
Meta
Hard
Data Scientist Locked

Diagnose sales correlations without claiming causality

This question evaluates a data scientist's competency in designing correlation-focused observational analyses, including exposure-window definition, c...

Analytics & Experimentation
1
0
31 people solved
Oct 13, 2025
Thumbtack logo
Thumbtack
Medium
Data Scientist

Compute weekly 3-week rolling sums in SQL

Using PostgreSQL, write a single query that outputs, for each calendar week in a given range, the sum of amounts in that week and a rolling sum over t...

Data Manipulation (SQL/Python)
0
0
7 people solved
Oct 13, 2025
Meta logo
Meta
Hard
Data Scientist Locked

Measure notification impact and set guardrails

This question evaluates causal inference, experiment design, metric specification and attribution, statistical power calculation, and long-term monito...

Analytics & Experimentation
2
0
20 people solved
Oct 13, 2025
Meta logo
Meta
Hard
Data Scientist Locked

Identify latent group-call demand from behavior

This question evaluates a data scientist's ability to design measurable product-analytics signals, infer latent user demand from event-level messaging...

Analytics & Experimentation
3
0
22 people solved
Oct 13, 2025
Uber logo
Uber
Medium
Data Scientist

Clean, split, merge, and aggregate with pandas

Given two CSVs, use pandas to clean, split strings, merge, and aggregate. drivers.csv driver_id,name,signup_city D1,Jane Doe,SF D2,Mark S,NYC D3,A...

Data Manipulation (SQL/Python)
0
0
4 people solved
Oct 13, 2025
Uber logo
Uber
Medium
Data Scientist

Write SQL for fares and age-band counts

You have two tables. Schema: - drivers(driver_id VARCHAR PRIMARY KEY, name VARCHAR, date_of_birth DATE) - trips(trip_id VARCHAR PRIMARY KEY, driver_id...

Data Manipulation (SQL/Python)
3
1
43 people solved
Oct 13, 2025
Uber logo
Uber
Medium
Data Scientist

Check anagrams under real-world constraints

Given two strings s and t, determine whether they contain exactly the same multiset of characters (e.g., 'abc' and 'cab' → true; 'aab' and 'ab' → fals...

Coding & Algorithms
4
0
84 people solved
Oct 13, 2025
Hard
Data Scientist Locked

Design a hybrid marketplace fraud system

This question evaluates competency in designing hybrid fraud detection systems, covering feature engineering across text, image, graph and telemetry s...

Machine Learning
3
0
43 people solved
Oct 13, 2025
TikTok logo
TikTok
Medium
Data Scientist

Write SQL for last-7-day metrics without windows

Assume today is 2025-09-01. Use ANSI SQL only and do not use window functions. You may use subqueries, GROUP BY, HAVING, and JOINs. Schema and small s...

Data Manipulation (SQL/Python)
0
0
10 people solved
Oct 13, 2025
Amazon logo
Amazon
Hard
Data ScientistSenior+ Locked

Design fraud detection across channels with unknowns

This question evaluates a data scientist's competence in designing and operationalizing multi-channel fraud detection systems, covering cost-sensitive...

Machine Learning
5
0
40 people solved
Oct 13, 2025
PayPal logo
PayPal
Medium
Data Scientist

Write SQL to flag Venmo ATO

SQL case: You are a Decision Scientist on Venmo’s Fraud (ATO) team. Using the schema and sample data below, write a single Standard SQL query that ret...

Data Manipulation (SQL/Python)
0
0
5 people solved
Oct 13, 2025
Meta logo
Meta
Medium
Data Scientist

Write SQL for social feed metrics and ties

You are given the following schema (PostgreSQL) and sample rows. Assume UTC timestamps and that friendships are static over the sample window. users(u...

Data Manipulation (SQL/Python)
1
0
14 people solved
Oct 13, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

Implement scalable prime generator

Write a function first_n_primes(n) that returns the first n prime numbers in ascending order. Constraints: - 1 ≤ n ≤ 100,000. - Aim for O(n log log n)...

Coding & Algorithms
4
0
53 people solved
Oct 13, 2025
Roblox logo
Roblox
Medium
Data Scientist

Implement deduped CTR/RPM aggregator over event stream

Implement a Python function to compute per-day, per-campaign CTR and RPM from an event stream with possible out-of-order and duplicate click events. I...

Data Manipulation (SQL/Python)
1
0
11 people solved
Oct 13, 2025
Roblox logo
Roblox
Medium
Data Scientist

Implement streaming CTR with deduplication

Implement a Python function to compute streaming, per-campaign CTR over a sliding 24-hour window with click de-duplication and late-arriving events. R...

Coding & Algorithms
8
0
88 people solved
Oct 13, 2025
Capital One logo
Capital One
Easy
Data Scientist Locked

Calculate Year-1 profit margin

This question evaluates a candidate's ability to perform applied financial math, including profit margin calculation, classification of costs into fix...

Statistics & Math
5
0
42 people solved
Oct 13, 2025