Intern Data Scientist Interview Questions
Data science internship interviews reward fundamentals over flash. These questions were reported by candidates interviewing for DS intern roles, so they cluster around what intern loops actually ask: probability and statistics, SQL queries, basic machine learning concepts, and lightweight, case-style problems that check whether you can reason about a metric or an experiment. The bar is approachable — interviewers know you don't have years of industry experience and listen for clear thinking and solid fundamentals rather than production ML. There are 40+ real, recently reported DS intern questions here across stats, SQL, ML, and case rounds, and most come with a worked solution so you can check your reasoning.
"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 and estimate Markov transition probabilities
A system is modeled as a discrete-time Markov chain over m states S = {s1, s2, ..., sm}. Part A (multi-step probabilities): - You are given a row-stoc...
Relate coefficients under linear feature transformation
This question evaluates understanding of linear regression parameter relationships under linear feature transformations, model equivalence and identif...
Evaluate and safely deploy a CVR model online
You have built a new CVR (conversion rate) prediction model for an RTB bidding system at a DSP. Offline metrics improved (e.g., lower log loss and hig...
Predict Stock Prices from Google Search Data
You are given access to historical Google search data — relative search volume over time for arbitrary query terms — along with standard historical ma...
Find Longest Increasing Continuous Subarray
Solve the longest increasing contiguous subarray problem in one pass. Includes Python code, edge cases, complexity, and a follow-up for returning the ...
Decide Whether an LSTM Is Appropriate for Sequence Data
You are considering an LSTM for a prediction problem with sequential observations. Explain what an LSTM is designed to capture, how you would prepare ...
Choose Between Precision and Recall for a Classification Decision
A binary classifier will support a real decision, and the model produces a probability score for each observation. Explain precision and recall, how t...
Count Closed Islands
This question evaluates a candidate's understanding of grid-based connectivity and the ability to detect enclosed regions, testing skills in graph rep...
Merge two sorted linked lists
This question evaluates proficiency with linked list data structures, pointer manipulation, in-place merging concepts, and algorithmic efficiency with...
Generate Uniform Samples and Estimate Percentiles
Solve two Google statistics questions: sample uniformly from a square using rand01 and estimate percentiles from histogram buckets using cumulative co...
Calculate Ultimate Loss by Policy Term
You work with insurance policy-term loss data. For a given policy term, its ultimate loss is defined as the sum of losses from the current term and al...
Compute Fibonacci Numbers
Write a function that returns the nth Fibonacci number. Definitions and requirements: - Use zero-based indexing: fib(0) = 0, fib(1) = 1. - For n >= 2,...
Coin-Flip Race to Four: Game Length and a Conditional Win Probability
Two players play a coin-flipping game with a single fair coin. The coin is flipped once per round. Every heads counts for Player 1, and every tails co...
Maximum-Product Simple Path in a Complete Directed Graph
You are given a complete directed graph with n nodes labeled 0 through n - 1. For every ordered pair of distinct nodes (i, j), there is a directed edg...
Explain approach and seek feedback effectively
Technical Screen: Communication in Live Coding and Internship Planning Part 1 — Live Coding Communication During a 20-minute live coding exercise foll...
Find two numbers that sum to target
Problem You are given an integer array nums (length n) and an integer target. Return the indices (i, j) such that: - i != j - nums[i] + nums[j] == tar...
Why Is the Sample Mean Approximately Normal for Large Samples?
In statistics we routinely treat the average of a large sample as if it were normally distributed — for example, when building confidence intervals fo...
Test whether two distributions differ
You have two datasets collected from different systems or populations, and you want to determine whether they come from the same distribution. Explain...
Count Enclosed Islands in a Grid
This question evaluates grid traversal and graph concepts such as connected-component detection, boundary-condition reasoning, and algorithmic time/sp...
Analyze a current event's market impact
World Event → Market Impact → Quant Modeling You are interviewing for a Data Scientist role on a quantitative team at a global bank. Choose one curren...