Statistics & Math Interview Questions
Practice 482 real Statistics & Math interview questions for 2026 — Statistics & Math interview questions gathered from actual interviews, with detailed solutions to guide your interview preparation. Covers companies like Meta, Capital One, Google, Amazon, and Optiver and roles such as Data Scientist, Quant/Trader, ML researcher, and Data Analyst. This collection is distinctive because problems range from applied inference

"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"

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"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."

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"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."

"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"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."
Contrast FCF vs NI; choose one statement
An asset-heavy company reports rising net income while free cash flow (FCF) is negative for three straight quarters. a) Explain when and why FCF can b...
Compute A/B significance, CI, and power
You run an A/B test for 7 days. Control A: 520 conversions out of 10,000 sessions. Variant B: 630 conversions out of 11,500 sessions. Use a calculator...
Optimize attempts in a timed logic test
Timed OA: Maximize Expected Score Under a Time Limit Context: You have 25 minutes (1,500 seconds) to attempt up to 30 multiple-choice items. You may c...
Compute two conditional probability scenarios
Probability — Two-Part Question Solve both parts. Show formulas and provide final numeric values. Part A — Coin Type Given HHH - A box has 5 coins: 3 ...
Analyze daily comments distribution and sampling
Daily Comments per Active User: Sampling and Inference You have, for a given day d, the count of comments made by each active user. Let there be m act...
Control confounding in observational ad lift
Estimating the ATE of Ad Exposure on Conversions (Observational Setup) You cannot randomize ad exposure. Users differ in age, education, income, and o...
Compute conditional occupancy across two rooms
Probability and Bayes Update: Two Rooms Setup There are two rooms. Prior over occupancy states: - With probability 1/3: both rooms are occupied. - Wit...
Quantify database bug cost/benefit
Bug Impact on Commission and Admin Costs (Jan–Mar) Context and Assumptions - The company earns commission revenue on user spend; an admin fee is a com...
Find premium share for break-even
Break-even Mix of Regular vs Premium Customers You are evaluating a two-tier customer model with a fixed total of 2,000,000 customers. Find how many m...
Derive variance and CTR confidence intervals
CTR as a Proportion: Estimation, Confidence Intervals, and Day-Level Variability Context: Click-through rate (CTR) is a proportion metric defined as C...
Estimate CTR lift with binomial tests and errors
A/B Test Inference, Peeking, and Multiple Comparisons You run a two-arm A/B test of click-through rate (CTR). - Control: n_c = 10,000,000 impressions,...
Explain Type I/II errors vs precision/recall
In the context of binary classification and hypothesis testing: 1) Define Type I error and Type II error. 2) Explain how they relate to false positive...
Compute stockout sufficiency probability
Probability That Muffins Suffice Setup - Each of the 5 remaining customers independently chooses one item: - Croissant with probability 0.7 - Muff...
Analyze Linear Regression Changes with Duplicated Observations
Linear Regression, p-values, and Chi-square with Large Samples Context You are analyzing regression and goodness-of-fit results. Consider what happens...
Solve two logic brain teasers
Two Classic Logic/Optimization Puzzles Puzzle 1: Heavier Ball with a Balance Scale You have 12 visually identical balls. Exactly one ball is heavier t...
Forecast and Analyze DoorDash Menu Price Inflation Gap
Question DoorDash wants to understand and forecast the difference between on-platform menu prices and the same items' in-store prices (the "inflation ...
Determine Probability of Video Selection and Impact Evaluation
Video Recommendation Push: Selection Probabilities, Complements, and Design Choices Scenario You are designing a push-notification system that recomme...
Estimate Family Proportions and Explain Regression Anomalies
On-site Statistics Round Task Overview You are given a population of families that have either 1, 2, or 3 children. You sample 100 children (i.e., the...
Derive Probability of Even Sum in Bernoulli Trials
Probability Puzzles: Parity and Runs Context You are given two independent probability problems commonly seen in data-science take-home assessments. A...
Calculate Probability of Heads and Red Balls Drawing
Quick-Fire Probability (CodeSignal-style) Context: Answer the following independent probability questions, using binomial (independent trials) and hyp...