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"
"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"
"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."
"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."
"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."
"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."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."
"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."
"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."
Test payment-accuracy lift with p-value and power
AB Test of Payment Accuracy (Two Proportions) Assume transactions in the two periods are independent and large enough for normal approximations. Defin...
Act when A/B result is not significant
A/B Test Planning and Decision-Making for a 60s Video Change Context: You are evaluating a product change with completion rate as the primary metric. ...
Choose tests and solve distribution parameters
Engagement Comparison: New vs Existing Users (2025-08-05 → 2025-09-01) Context: You have per-user daily session counts (integer, skewed, many zeros) f...
Estimate first selection round with/without replacement
Probability of First Selection Across Rounds Context: There are 1,000 people. Each round, 10 draws are made. Consider a fixed person. Case 1: Without ...
Compute wallet-link probabilities, expectation, and conditionals
Question Coinbase users each independently link a wallet with probability p. Work through the full probability model for this process. 1. General form...
Choose group-call participant cap via distribution
Group Call Cap Decision: QoS vs Reach You are deciding whether to cap the maximum number of participants in a group call. You have the past 28-day dis...
Apply instrumental variables under interference
IV estimation for a ride‑sharing feature when A/B testing is infeasible due to interference Context You need to estimate the causal effect of a new ri...
Calculate power and test duration
A/B Test Sizing: Reducing Cold-Food Complaint Rate You are running an A/B test of thermal delivery bags aiming to reduce the cold-food complaint rate....
Compute posterior and event counts in fraud screen
Fake-Account Screening with Threshold on 5 Signals You are designing a rule-based screener that flags an account if at least k of 5 binary signals fir...
Compute power and interpret guardrails
Context You ran a 1-week A/B test of a new search ranking with clustered randomization at the DMA level: 100 DMAs total (50 control, 50 treatment). Ou...
Price a coin-doubling game rationally
Coin-Doubling (St. Petersburg) Game: EV, Log-Utility Pricing, Kelly Staking, and House Cap Context and assumptions - Single play: You buy one ticket t...
Calculate first-year profit margin
Profit Margin Calculation (Year 1) Context: A single product is sold in Year 1. m denotes million. Given: - Fixed costs: $375m - Units sold (Regular):...
Test classifier difference with McNemar's test
Paired Comparison of Two Classifiers via McNemar's Test You evaluated two classifiers on the same 10,000 labeled examples and summarized the paired ou...
Diagnose and fix selection bias in experiments
Selection Bias With Opt-in Discount Banner Context You observe that users can opt in to see a discount banner (treatment = 1 if they opted in and saw ...
Apply PSM rigorously for observational A/B analysis
Task: Estimate ATT on 7-Day Retention Using Propensity Score Matching (PSM) Context You are given observational, user-level product data where users s...
Explain Bayes’ Theorem and P-Value in Decision-Making
Statistics Fundamentals: Bayes' Theorem and p-Values Context Stakeholders want clear, decision-focused explanations of two foundational concepts used ...
Determine Probability of Friend Request Being Fake
Scenario You operate a platform where 95% of accounts are real and 5% are fake. Fake accounts send 10 times as many friend requests per account as rea...
Estimate Default Rates Using Logistic Regression Model
On-site Statistical Role Play: Estimate Credit-Card Default Probability for a New Customer Segment Context You have historical account-level data with...
Analyze survey with gender imbalance
Scenario You ran a user survey to measure satisfaction with a new product feature. Each respondent reports: - gender ∈ {female, male} - satisfaction (...
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...