Data Scientist Statistics & Math Interview Questions
Practice 471 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 Optimal Die Re-roll Strategy
This question evaluates a candidate's understanding of optimal stopping, expected-value computation, and decision-making under uncertainty in probabil...
Explain why the t-statistic helps
Suppose you estimate an effect size \(\hat{\beta}\) in a regression model or an A/B test and compute a standard error \(SE(\hat{\beta})\). Explain why...
Explain Bootstrap and Prove Uniformity
This question evaluates mastery of statistical inference and probability theory, testing knowledge of resampling methods (bootstrap), interpretation o...
Derive the Gambler's Ruin Probability
A gambler starts with i coins. Each round independently increases the fortune by one with probability p and decreases it by one with probability 1-p. ...
Compute probabilities and expectations in random processes
This is a rapid-fire probability and expectation round: a sequence of short, self-contained brain-teasers solved on a whiteboard. The interviewer expe...
Compute Commuter Ride Probabilities
This question evaluates competency in probability theory—specifically conditional probability, marginalization, Bayesian inversion, and expectation of...
Answer four core statistics questions
Problem set (timed) Answer the following four questions. 1) Covariance of order statistics Let \(X\) and \(Y\) be independent \(\mathrm{Unif}(0,1)\). ...
Find constant minimizing absolute error
This question evaluates understanding of L1 loss minimization, robust central-tendency estimators, and order-statistics reasoning for point estimation...
Calculate Triangle Probability From Broken Stick
A stick of length 1 is broken into three pieces by choosing two cut points independently and uniformly at random along the stick, then sorting the two...
How would you critique this regression?
Question You are reviewing a modeling workflow built by another data scientist and asked to critique it. Business context A website receives traffic f...
Interpret and Regularize Regression Models
This question evaluates a data scientist's competency in regression model interpretation, hypothesis testing for coefficients and p-values, outcome tr...
Solve the 12-coin balance puzzle
The 12-Coin Counterfeit Puzzle (Three Weighings) You are given 12 visually identical coins. Exactly one of them is counterfeit. The counterfeit coin d...
Compute an A/B test p-value by hand
In an A/B test on a game feature, you measure conversion rate (binary outcome). - Control: n₁ = 1000 users, x₁ = 120 conversions - Treatment: n₂ = 980...
Sketch distributions and compare mean/median/mode
This question evaluates understanding of distributional shape, central tendency (mean, median, mode), skewness, outliers, and the effects of combining...
Calculate a Confidence Interval
Suppose an online experiment compares treatment and control on conversion rate. Treatment has x1 conversions out of n1 users, and control has x0 conve...
Why Use a t-Statistic?
This question evaluates understanding of the t-statistic as a standardized measure for testing whether an estimated effect differs from zero, covering...
Compute Groupon unit economics and break-even
Restaurant Coupons and Unit Economics Context: A restaurant's variable cost (VC) is 40% of pre-discount spend and fixed cost (FC) is $100/day. Assume ...
Why is the t-statistic useful
This question evaluates understanding of the t-statistic and broader statistical inference competencies, focusing on interpreting effect size relative...
Compute probability match lasts 5 games
Two players play independent games of table tennis. - Player A wins each game with probability \(p\) (constant across games). - They play a best-of-5 ...
Choose Classification Metrics Under Asymmetric Costs
You are evaluating a binary classification model for a business problem. Explain how to use a confusion matrix to compute and interpret: - precision, ...