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."
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...
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...
Perform no-calculator math accurately and fast
Technical Screen: Mental Math and Estimation Solve quickly without a calculator. For each, show the brief mental shortcut you use. Problems - (a) 37 ×...
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...
Choose threshold under costs and uncertainty
Incentive Targeting: Threshold Selection, Uncertainty, Calibration, and Drift Context: You deploy a model that sends an incentive to predicted positiv...
Derive and validate DID for staggered rollout
Causal Effect of a Staggered Adoption Policy Across EU Regions You cannot randomize. An intervention is rolled out at different dates across EU region...
Analyze HT vs HH stopping-time probabilities
Coin-Flip Stopping Game: HT vs HH You repeatedly flip a coin until either the pattern HT appears (Player A wins) or the pattern HH appears (Player B w...
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...
Design an A/B test; choose Z vs T
A/B Test on a Signup Funnel: Sample Size, Test Choice, Sequential Design, and Causal Plan Context You are planning a two-variant A/B test on a signup ...
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...
Estimate constant under absolute loss
Suppose you have observed target values \(y_1, y_2, \dots, y_n\), and you want to fit the simplest possible model that predicts the same constant valu...
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...
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...
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...