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Data Science and Data Engineering Interview Questions

Data interviews combine SQL and coding, statistics or modelling for data scientists, pipelines and data modelling for data engineers, and behavioural questions about working with stakeholders and turning analysis into decisions.

Below are 20 questions asked in data science and data engineering interviews, each with a sample answer and tips. Read the answer, then practise it out loud: InterviewGuru's AI mock practice scores your spoken or typed answer out of 10 and shows what to improve.

🎯 What interviewers look for
  • Framing a business question as an analysis or a metric before reaching for a model
  • Statistics you can explain simply: experiments, significance, bias and leakage
  • Pipelines that are reliable: batch versus streaming, idempotent jobs, data quality checks, schemas
  • Trade-offs between accuracy, latency, cost and interpretability
  • Stories where your analysis changed a decision, and how you communicated uncertainty
Job Offer Negotiation (2)
How do you negotiate a signing bonus to offset unvested stock or a missed annual bonus at your current job?Medium How do you ask for more information about the company's equity grant (strike price, valuation, dilution)?Medium
Product Sense (2)
If you noticed a 15% drop in daily active users (DAU) for our core web product, how would you investigate it?Hard How would you measure the success of a newly launched real-time collaboration feature?Medium
System Design (6)
Design a web crawler that indexes billions of web pages.Hard Design a distributed logging and metrics monitoring platform (like Datadog).Hard Design a location-based nearby places service (like Yelp or Google Maps nearby search).Medium Design a metrics aggregation and anomaly detection pipeline for IoT sensor data.Hard Design a content recommendation feed (like Twitter or Instagram home feed).Hard Design a high-volume email campaign sending platform (like Mailchimp).Hard
Technical (7)
What is Database Indexing, and how do B-Trees compare to Hash Indexes?Medium Explain the four ACID properties in relational databases and how isolation levels work.Hard What is the difference between SQL and NoSQL databases, and when should you use each?Easy Explain the CAP theorem and PACELC theorem in distributed systems.Hard Explain the differences between SQL Joins: INNER, LEFT, RIGHT, FULL OUTER, and CROSS joins.Easy What is Sharding in database systems, and how do Range-Based and Hash-Based sharding compare?Hard What is the N+1 query problem in Spring Data JPA, and how do you fix it?Medium
Coding (3)
Find the maximum subarray sum in an integer array `nums` (Kadane's Algorithm).Medium Given an array of integers `height` representing an elevation map, compute how much water it can trap after raining (Trapping Rain Water).Hard You are given an integer array `coins` and an integer `amount`. Return the fewest number of coins needed to make up that amount, or -1 if impossible (Coin Change).Medium

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