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."
Prove OLS invariance to linear transforms
You fit Model 1: y ~ X1 + X2. You also fit Model 2 using Z = [X1 − X2, X1 + X2] = X T where T = [[1,1], [−1,1]] (2×2, invertible). a) Prove that OLS p...
Compute p-values, probabilities, and regularization choices
Answer all parts. A) Hand‑compute a two‑sided p‑value comparing two means using Welch’s t‑test. Sample A: n1=20, mean1=5.2, sd1=1.1. Sample B: n2=24, ...
Analyze the Accident-Rate Spike
A monthly line chart shows the accident rate for Uber trips in one city. The accident rate increases sharply from June through November, then drops qu...
Choose better bank queue and describe distributions
This question evaluates probabilistic reasoning and statistical intuition—queueing theory for expected waiting time and variability plus distributiona...
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...
Explain Linear Regression Assumptions
This question evaluates understanding of ordinary least squares linear regression assumptions and their implications for unbiased coefficient estimate...
Calculate Precision, Recall, and F1
Question You are given a list of binary classification outputs, where class 1 is the positive class. Each record contains: - actual (INT, 0 or 1) - pr...
Analyze data duplication effects in linear regression
OLS With Duplicated Observations: Estimator, Variance, and Inference Pitfalls Context: You have the linear model y = Xβ + ε with full-rank X ∈ ℝ^{n×p}...
Justify synthetic control and handle inference
Synthetic Control: Assumptions, Estimation, Inference, and Diagnostics Context You are estimating the causal effect of an intervention on a single tre...
Understand Simpson's Paradox with Simple Examples
Understand Simpson's Paradox with Simple Examples Scenario You are a data scientist advising a product team on statistical analysis and experimental d...
Solve Market-Risk and Probability Questions
Question Answer the following quantitative interview questions for a market-risk / data-scientist screen at Morgan Stanley. 1. Stress testing WTI and ...
Solve Markov, OLS-rotation, and coin-toss probability
Answer the following three interview questions. 1) Basic properties of a Markov (transition) matrix Let \(P\) be a transition matrix of a (time-homoge...
Derive logistic regression and thresholds
Logistic Regression Deep Dive (Binary Classification) Assume a binary classification setting with observations {(x_i, y_i)} for i=1..n, where x_i ∈ R^...
Compute robust inference under skew and outliers
This question evaluates a data scientist's competency in robust statistical inference for A/B testing, covering handling of skewed continuous outcomes...
Derive expectation for two consecutive heads
Waiting Time Until First HH (Two Consecutive Heads) Setup Let T be the number of coin flips required until the pattern HH (two consecutive heads) appe...
Compute sample size and analyze A/B results
A/B Test: Sample Size, Sequential Correction, and Post-Experiment Analysis Context You are planning a two-arm A/B test with a binary (Bernoulli) conve...
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 ...
Compute P(A>B) for m- and n-sided dice
Two fair dice are rolled independently: - Die A has m faces labeled \(1,2,\dots,m\). - Die B has n faces labeled \(1,2,\dots,n\). Each face is equally...
Calculate Annual Profit of Credit Card Portfolio
Credit Card Portfolio Annual Profit You manage a portfolio of 500,000 active credit-card accounts. Each active card generates multiple revenue streams...
Analyze Linear Regression Changes with Duplicated Observations
Linear Regression, P-values, and Chi-square with Large Samples You are analyzing regression and goodness-of-fit results. Consider what happens if ever...