Tech Interview Questions

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Machine Learning Engineer + Data Scientist + Software Engineer Interview Questions

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9.2k Questions 486 Companies08.11.2026
Showing 20 results
Role
Google logo
Google
Hard
Data Scientist Locked

Diagnose and fix flawed model fit

This question evaluates a data scientist's competency in applied supervised learning diagnostics, including feature encoding, feature scaling, class i...

Machine Learning
8
0
64 people solved
Oct 13, 2025
Flatiron Health logo
Flatiron Health
Medium
Data Scientist

Compute sample size and significance

You are planning a two-variant A/B test with equal allocation and a binary primary metric (conversion). Baseline rate p0 = 0.045. You want to detect a...

Statistics & Math
5
0
62 people solved
Oct 13, 2025
Citibank logo
Citibank
Medium
Data Scientist

Diagnose and fix linear regression assumption breaks

OLS Assumptions, Diagnostics, Remedies, and Refitting Under Heteroskedasticity and Multicollinearity You are fitting a linear regression with Ordinary...

Machine Learning
8
0
70 people solved
Oct 13, 2025
TikTok logo
TikTok
Hard
Data Scientist

Explain and tune XGBoost; prevent overfitting

XGBoost Tree Booster: Objective, Hyperparameters, Tuning for Imbalanced Detection, and Post-training Use Context: You are building a binary classifier...

Machine Learning
4
0
66 people solved
Oct 13, 2025
Pinterest logo
Pinterest
Hard
Data Scientist

Design rigorous A/B test and causal analysis

Experiment Design and Causal Inference: Multi-part Problem Context: You are designing a high-traffic web A/B test on a binary conversion metric. Answe...

Statistics & Math
16
0
143 people solved
Oct 13, 2025
Capital One logo
Capital One
Medium
Data Scientist

Compute optimal stopping in a die-rolling game

Optimal stopping with a fair die (3-roll horizon) You observe outcomes of fair six-sided die rolls (faces 1–6) and may stop after any roll to take the...

Statistics & Math
9
0
167 people solved
Oct 13, 2025
Capital One logo
Capital One
Medium
Data Scientist

Design theme-park profit model and bid decision

Theme Park Pricing and Land-Acquisition Case Context You manage pricing analytics for a Disney-like theme park. Baseline demand is steady. A land auct...

Analytics & Experimentation
13
0
87 people solved
Oct 13, 2025
Thumbtack logo
Thumbtack
Medium
Data Scientist Locked

Optimize red-ball draw probability, prove optimality

This question evaluates probabilistic reasoning, optimization and mathematical proof skills by asking how to allocate red and blue balls across two bo...

Statistics & Math
7
0
66 people solved
Oct 13, 2025
Thumbtack logo
Thumbtack
Hard
Data Scientist

Design and evaluate an A/B test for launch

A/B Test Design: New Matching Model for a Two‑Sided Marketplace Context You are testing a new matching/ranking model that determines which providers a...

Analytics & Experimentation
6
0
59 people solved
Oct 13, 2025
Capital One logo
Capital One
Hard
Data Scientist

Design A/B test for credit card offer

A/B Test Design: New Credit-Card Acquisition Flow (Revised APR Disclosure + Signup Bonus) Context You are launching a new credit-card acquisition flow...

Analytics & Experimentation
11
0
114 people solved
Oct 13, 2025
Google logo
Google
Hard
Data Scientist Locked

Design and critique an abuse-detection ML system

This question evaluates system-design and production machine learning competencies including large-scale classification versus risk scoring, handling ...

Machine Learning
10
0
98 people solved
Oct 13, 2025
Capital One logo
Capital One
Hard
Data Scientist

Design and analyze a card signup A/B test

A/B Test Design: Co‑Branded Gym Credit Card Offer Context: You will A/B test a 3‑month free gym membership offer shown on the application landing page...

Analytics & Experimentation
8
0
80 people solved
Oct 13, 2025
Perplexity AI logo
Perplexity AI
Hard
Software Engineer

Diagnose overloaded Kubernetes cluster

Kubernetes Overload: End-to-End Debug + Mitigation Plan You are given a Kubernetes-based microservices system that is currently overloaded, exhibiting...

System Design
11
0
98 people solved
Aug 13, 2025
Remitly logo
Remitly
Hard
Software Engineer

Design a Production-Ready URL Shortener

System Design: Production-Ready URL Shortening Service Goal Design a production-ready URL shortening service that can issue short links, resolve them ...

System Design
9
0
89 people solved
Aug 13, 2025
Remitly logo
Remitly
Hard
Software Engineer

Whiteboard and Deep Dive a Past Project

System Design: End-to-End Architecture Walkthrough Prompt Whiteboard the end-to-end architecture of a complex, user-facing system you led. Cover: 1. M...

System Design
8
0
93 people solved
Aug 13, 2025
Palantir logo
Palantir
Easy
Software Engineer

Find Shortest Paths in Road Network

You are reviewing code for a road-network graph. The domain objects are: `java class Location { String name; Location(String name) { this.name...

Coding & Algorithms
2
0
19 people solved
Mar 8, 2026
Google logo
Google
Easy
Data ScientistSenior+

Explain mixed models and fixed vs random effects

In an applied DS setting, you are modeling an outcome (e.g., watch time per session, conversion, or rating) across multiple entities (e.g., users, cre...

Statistics & Math
13
0
97 people solved
Oct 13, 2025
Adobe logo
Adobe
Medium
Machine Learning Engineer Locked

Explain leakage, missing data, and common losses

This question evaluates a candidate's understanding of data leakage, strategies for handling missing data, and the differences between loss functions ...

Machine Learning
11
0
112 people solved
Jan 13, 2026
Adobe logo
Adobe
Medium
Machine Learning Engineer Locked

Implement K-means clustering from scratch

This question evaluates a candidate's understanding of clustering algorithms and practical implementation skills in unsupervised machine learning, inc...

Coding & Algorithms
8
0
121 people solved
Jan 13, 2026
LinkedIn logo
LinkedIn
Easy
Machine Learning Engineer Locked

Explain overfitting vs underfitting and fixes

This question evaluates understanding of model generalization in supervised machine learning, focusing on the concepts of overfitting and underfitting...

Machine Learning
10
0
108 people solved
Feb 8, 2026