Statistics & Math Interview Questions
Practice 481 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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"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."
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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."
"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."
"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."
Solve Classic Probability Questions
An onsite interview included the following independent probability and expectation questions: 1. Squid Game bridge problem. In the classic glass-bridg...
Explain and resolve Simpson’s paradox
Define Simpson’s paradox and construct a concrete numeric example where group-wise success rates favor treatment in each subgroup but the aggregate ra...
Choose tests under non‑normal, unequal variance
Heavy-Tailed, Heteroskedastic Metrics in A/B Tests (AOV example) Context: You are comparing two groups in an A/B test on a spend metric (e.g., Average...
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...
Estimate billboard reach and impressions
Digital Billboard: Weekly Reach, Impressions, and Store-Visit Attribution Context You are estimating the performance of a single digital billboard bes...
Solve numeric sequence pattern puzzles
Sequence Prediction Task You are given five independent number sequences. For each, determine the next term and briefly explain the rule you used. Ass...
Derive MLE and Bayesian posterior for Bernoulli
Bernoulli/Binomial Inference Task You observe n independent Bernoulli trials with unknown success probability p, and you record k successes (so K ~ Bi...
Diagnose and interpret regression assumptions
OLS for Signups with Diagnostics and Alternatives You are given a cleaned dataset with the following columns: - signups: non-negative integer count ta...
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...
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,...
Test coin fairness from 560 tails in 1000 flips
You flip a coin n = 1000 times and observe 560 tails. At significance level α = 0.05, test whether the coin is fair. - State the null and alternative ...
Plan for timed probability assessment
Timed Probability/Statistics Assessment Strategy Company: Optiver · Role: Software Engineer You are taking a timed online assessment of 30 probability...
Determine departure time from travel times
Canoe and River Current Timing Context Two friends paddle on a river with a constant current of 2 mph. Their paddling speed relative to the water is c...
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 ...
Model wins-until-failure and expected future wins
You are given a DataFrame df where each row summarizes a player’s performance until their first loss. Input df columns: - player_id (string/int) - win...
Explain confounding with an Uber example
Question You are interviewing for a Data Scientist role and are given access to Uber / Uber Eats data. Answer the following about confounding in causa...
Calculate conditional probabilities for coin tosses
Probability with Two Fair Coin Tosses You toss a fair coin twice. Let the coin be fair (P(H) = P(T) = 1/2) and the tosses independent. (a) Compute P(s...
Explain Bootstrap and Prove Uniformity
You are interviewing for a Data Scientist role. Answer the following statistics-theory prompts: 1. What is the bootstrap, when would you use it, and c...
Compute P(third Ace | Ace in first two)
Conditional probability with cards drawn without replacement Problem You draw three cards without replacement from a standard 52‑card deck (4 Aces). G...
Compute profit and break-even for memberships
Grocery Loyalty Program Economics — Year‑1 Incremental Profit and Premium Break‑Even Context: You are evaluating the Year‑1 unit economics of a grocer...