Statistics & Math Interview Questions
Practice 489 real Statistics & Math interview questions for 2026. Statistics & Math interview questions from actual interviews with detailed solutions focused on the quantitative thinking companies expect: probability intuition, estimation, hypothesis testing, experimental design, and the algebraic reasoning behind A/B test diagnostics. This collection targets the sort of questions you’ll see in data scientist, analytics, and quantitative roles and is built for serious interview preparation. What interviewers evaluate most are clear probabilistic reasoning, correct assumptions about sampling and bias, the ability to design and interpret experiments, and concise verbal math under time pressure. Expect this category to be weighted heavily at companies like Meta, Capital One, and Google — and to appear across screens, take-home case problems, and onsite analytics/product rounds. To prepare effectively, practice fast, auditable derivations, explain assumptions out loud, and rehearse structured approaches to experimental tradeoffs and edge-case thinking.
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Answer four core statistics questions
Problem set (timed) Answer the following four questions. 1) Covariance of order statistics Let \(X\) and \(Y\) be independent \(\mathrm{Unif}(0,1)\). ...
Estimate population singletons from a 10% log
A daily search log has one row per query string. You draw a 10% simple random sample of rows without replacement. Define a “unique query” (singleton) ...
How do you derive CDF from a PDF?
You are given a continuous random variable \(X\) with probability density function (PDF) \(f_X(x)\). 1. Write the definition of the cumulative distrib...
Explain and interpret p-values correctly
Context You are evaluating a change to a fraud decision rule (e.g., a new threshold or step-up authentication rule). You run an experiment comparing C...
Compute probability an account is fake
A platform uses an automated classifier to flag potentially fake accounts. Assume: - Base rate: 2% of accounts are fake. - The classifier flags a fake...
Explain BLS vs CLS; compute t-stats
Part A — Concepts: Define Brand Lift Study (BLS) vs Conversion Lift Study (CLS) in ads measurement. List key bias/variance sources for each (e.g., non...
Choose better bank queue and describe distributions
You are interviewing for a data role and are asked several probability/distribution questions. 1) Bank queue choice (queueing intuition) A bank has 5 ...
Compare Normal vs Poisson; test dispersion and approximate tails
You collect n=200 independent minute-level event counts with sample mean x̄=14.5 and sample variance s²=16.2. 1) Under a Poisson(λ) model, derive the ...
Find probability of overlapping blooms
Overlap Probability of Two Random Bloom Periods Assumptions - Time is measured in days over a 30-day horizon. - Each flower begins blooming once, at a...
Can bootstrap help reduce variance
An interviewer asks: “Can bootstrap help reduce variance?” Answer this question precisely. Distinguish between: 1) Using the bootstrap to estimate var...
Compare Normal and Poisson Distributions in Statistics
Comparing Normal and Poisson Distributions You are modeling event counts, such as number of clicks, and continuous measurements, such as response time...
Define and compute surge pricing metrics
Surge Pricing Metrics, Formulas, and Causal Estimation You are evaluating surge pricing in a two-sided marketplace (customers place requests; drivers/...
Solve relative-truth cat puzzle
Logic Puzzle: Directed Truth/Lie Rule and Cat Counts Three people (Asta, Bronya, Clara) each own a different number of cats (positive integers). When ...
Solve animals-and-legs count
Barn Legs Puzzle (Linear Equations) Convert the word problem into a small system of linear equations and solve. You have a barn with three types of an...
Choose the right test for proportions
A/B Test on Delivery Completion Rate (Binary Outcome) Context: You are evaluating an A/B test on a binary metric (delivered_bool). Treat each order as...
Differentiate P-value and Confidence Interval in Statistics
Differentiate P-value and Confidence Interval in Statistics Statistics Knowledge Check (Onsite Data Scientist) Task Explain core inferential statistic...
Explain Linear Regression Assumptions
Suppose you are using ordinary least squares linear regression to model a continuous business outcome such as weekly user spend from several features,...
Correct length-biased sampling from family-size survey
In a town, you visit a school and ask 100 kids: “How many children are in your family?” You observe: - 50 kids say their family has 1 child - 20 kids ...
Prove and apply statistical ML fundamentals
Technical ML/Statistics Exercises (with precise math and small computations) Assume a standard supervised learning setting with n samples, p features,...
Solve probability and expectation problems
Probability and Expectation Practice (Take‑home) Assume all coins and dice are fair unless stated otherwise. Show reasoning and final results. 1) Thre...