Onemain financial Data Scientist Interview Questions
Master your tech interview with our curated database of real questions from top companies.
Determine Optimal Marketing Budget Allocation for Maximum Profit
Budget Allocation Across Acquisition Channels Context You are given an Excel sheet with per-channel performance metrics for three acquisition channels...
Count, Return, Find, and Select in SQL Queries
orders +----------+--------------+------------+--------+ | order_id | customer_id | order_date | amount | +----------+--------------+------------+---...
Handle Missing Values and Outliers in Machine Learning
Technical Screening: Model Development Discussion Context You are building classification and regression models on tabular business data with missing ...
Calculate Profit-Maximizing Price and Validate with Additional Data
Profit-Maximizing Price with Fixed/Variable Costs and a Price–Demand Curve Context You sell a single software product at one price P. You are given: -...
Present Successful Analytics Project: From Problem to Impact
Behavioral Panel: 10–15 Minute End-to-End Project Presentation Scenario Onsite panel presentation (10–15 minutes) with 4–5 listeners. Prompt Choose on...
Explain Type I and Type II Errors in Hypothesis Testing
Statistics Fundamentals: Type I vs Type II Errors and A/B Test Trade-offs Task You are discussing hypothesis testing in the context of a past modeling...
Optimize Credit-Card Strategy: Pricing, Limits, and Target Segments
Credit-Card Business Optimization Case Context You are evaluating a new credit-card product. You have (or will estimate) per-segment cost, revenue, an...
Solve Python Challenges: Reverse String, Palindrome, Fibonacci, Unique List
Scenario Live coding round – four quick Python exercises Question Implement a function that reverses a string in-place. Write code that returns True i...
Present a project to non-technical leaders
10–15 Minute Modeling Project Presentation (Mixed Stakeholders) Task Prepare a 10–15 minute presentation of a past modeling project for a mixed audien...
Implement an LRU cache with O(1) ops
Design and code an LRU cache supporting get(key) and put(key, value) in O(1) average time with capacity N. Specify your data structures, handle update...
Maximize credit card portfolio profit
Credit Card Approval and Profit Optimization (12‑month horizon) Context You receive 10,000 credit card applications per month. Applicants are grouped ...
Optimize SaaS pricing and profit
SaaS Pricing: Linear Demand, Capacity Constraint, and Subscription Churn Context: You are pricing a single-seat SaaS product (one seat per customer pe...
Transform clickstream with pandas sessionization
Given a pandas DataFrame events with columns [user_id:int, ts:str ISO8601 or NaT, url:str, server_log_ts:datetime], build 30-minute inactivity session...
Write SQL for cohort retention and ARPU
Using PostgreSQL, compute monthly signup cohort D30 retention and 30-day ARPU. Cohort month = date_trunc('month', signup_date). D30 retention = users ...
Choose evaluation metrics for imbalanced risk model
Cost-Sensitive Fraud Detection: Thresholding, Metrics, and Calibration Assume a binary fraud classifier outputs calibrated probabilities p = P(y=1|x)....
Handle missing data and outliers robustly
Customer Churn Modeling: Preprocessing, Missingness, Outliers, and Evaluation Context You are building a binary churn model for a consumer subscriptio...
Select and tune XGBoost hyperparameters
Binary Classification Under Compute and Imbalance Constraints Context You are training an XGBoost model for a binary classification problem with: - 1,...
Differentiate and control Type I/II errors
A/B Test Powering and Error Control (Two-Proportion Z-Test) Context: You are planning a two-arm A/B test on sign-up conversion. The current baseline c...
Calculate Break-even for New Credit Card Product Launch
Break-Even for a Credit Card with Annual Fee, Interchange, and Cashback Context You are evaluating a new credit-card product. Revenue comes from: - An...
Calculate Break-Even Point and Profit Impact Analysis
Break-even and Profit Sensitivity for a Restaurant Context A restaurant has fixed monthly costs (rent, salaries) and a variable cost per customer (foo...