Data Scientist Statistics & Math Interview Questions
Practice 455 real Statistics & Math interview questions for Data Scientist roles. From companies including Meta, Capital One, Google, Amazon, Uber.
"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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"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."
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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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"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."
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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."
Calculate Posterior Probability Using Bayes' Theorem Example
Bayes' Theorem: Spam-Flag Posterior You are evaluating a simple classifier that flags messages as spam. From historical data you know the spam prevale...
Compare queueing systems and common distributions
Question You are asked a series of statistics fundamentals questions in a data science technical screen. 1. Queueing. A bank with 5 tellers can be org...
Design human review to estimate model accuracy
You need to estimate the accuracy of an ML classifier on a population of subjects. You can only afford K total human reviews. Each human review produc...
Calculate Probability of Heads in Coin Flip Experiment
Coin Flips: Counting and Binomial Probabilities Context Assume 10 independent flips of a fair coin (probability of heads p = 0.5 for each flip). Each ...
Calculate Expected Users Adopting Wallet Feature
Wallet Feature Adoption – Probability and Expectation Setup - You are analyzing adoption of a new wallet feature. - There are N users. Each user indep...
Differentiate P-value and Confidence Interval in Statistics
Statistics Knowledge Check (Onsite Data Scientist) Task Explain core inferential statistics concepts and when to apply common hypothesis tests. Questi...
Determine Conditions for Multiplying Event Probabilities in Statistics
Scenario You are modeling multiple, distinct risk events in Coinbase Wallet (e.g., E1, E2, …, En) and want the probability that all occur, or that non...
Understand Simpson's Paradox with Simple Examples
Scenario You are a data scientist advising a product team on statistical analysis and experimental design. Tasks 1) Simpson’s paradox - Explain Simpso...
Identify P-Value Limitations and Complementary Approaches
A/B Testing: Limits of P-values and Better Decision Practices Scenario Your team is running an A/B test for a new product feature and stakeholders rel...
Calculate Posterior Fraud Probability Using Bayes' Theorem
Posterior Fraud Probability After a Flag Context You operate a fraud detection system that flags accounts as suspicious. Define: - F: account is fraud...
Compute answers to probability and counting puzzles
Below are several independent interview-style math/logic questions. 1) Barn legs You see only spiders, chickens, and cows in a barn. - Total legs = 56...
Generate Uniform Samples and Estimate Percentiles
Answer the following two probability/statistics questions. 1. You are given access to a function rand01() that returns independent samples from Unifor...
Compute Markov steady state and expectations
Probability and Game Theory: Three Sub-questions Context: The exact transition matrix P (for Q1) and the 2×2 payoff matrix (for Q3) are not provided. ...
Estimate percentile from buckets
You are given an approximate histogram of search-query frequencies. Each bucket i is represented as (left_bd_i, right_bd_i, bucket_count_i), where: - ...
Compute Bayes probability for fake accounts
A platform is trying to detect fake accounts. Assume: - Base rate of fake accounts is \(P(F)=p\). - A detection system flags an account as suspicious ...
Determine roles from B's accusation
Knights and Knaves: Single Statement Inference You meet two islanders, A and B. Each person is either a knight (always tells the truth) or a knave (al...
How to derive correlation from variances
You have two random variables X and Y. You are given: - Var(X + Y) - Var(X) 1) Is the correlation Corr(X, Y) identifiable from only these two quantiti...
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...
Calculate Ad Insertion Statistics for Two Methods
Scenario Evaluating two ad-insertion strategies in a 100-post feed. - Option A (independent placement): Each post independently becomes an ad with pro...
Determine Probability of Both Children Being Boys
Scenario A classic conditional-probability brain-teaser used in data science screens to test probabilistic reasoning and the discipline of stating ass...