Senior+ Data Scientist Interview Questions
Senior+ data scientist interviews go deep on experimentation and inference, not just SQL and modeling basics. These questions were reported by candidates interviewing for senior+ DS roles, so they reflect what senior+ loops actually push on: A/B test design and analysis, causal inference when you can't run a clean experiment, metric definition and ownership, and the product judgment to turn an analysis into a decision. At the senior+ level interviewers also probe how you think about ML systems end to end — framing, evaluation, and the trade-offs behind a model in production — and how you influence stakeholders with a result. There are 70+ real, recently reported senior+ data scientist questions here across experimentation, statistics, SQL, ML, and case rounds. Most come with a detailed solution or strong-answer guidance so you can calibrate to the senior+ bar.

"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."
Explain why IG Story usage exceeds Facebook
Explain why IG Story usage exceeds Facebook Product analytics case: Instagram vs Facebook Stories You work on Stories across two apps: Instagram (IG) ...
Write SQL/Python for ACH fraud analytics
As of today (2025-09-01), use the following schema and tiny samples to answer. Provide SQL for the SQL parts and Python for the Python part. Schema - ...
Implement streaming k-way merge with constraints
Implement a function merge_k(iterators, N) that returns the first N items of the global ascending order from k sorted, potentially unbounded iterators...
Demonstrate influential product leadership under ambiguity
Behavioral & Leadership: Influencing Without Authority Under Tight Deadlines Scenario You are a Senior Data Analyst supporting a streaming product. Fo...
Design a reproducible data pipeline for modeling
You receive raw clickstream events and a user table. Build a reproducible daily pipeline that outputs user-day features for modeling. It must be idemp...
Explain mixed models and fixed vs random effects
In an applied DS setting, you are modeling an outcome (e.g., watch time per session, conversion, or rating) across multiple entities (e.g., users, cre...
Convert Dictionary to DataFrame
Using Python and pandas, convert the following dictionary into a DataFrame. Each top-level key is a target column name, and each value is a list of [r...
Answer ownership and ambiguity behavioral questions
Answer behavioral interview prompts for a Data Scientist working in risk or product analytics: 1. Tell me about a time data changed a decision. 2. Whe...
Explain Shell Script Line-by-Line for Data Science Workflows
Scenario Technical screening for a Principal Data Scientist: reviewing shell script and Python classes Question Explain, line by line, what the provid...
Compute invalid event percentage by pixel
Context You work on an ads pixel instrumentation platform. Each pixel emits events throughout the day; some events are missing (not observed) and some...
How would you measure causal impact?
Answer the following two analytics interview prompts. Constraints & Assumptions - For causal impact, separate prediction from causal identification. -...
How would you test billboard effectiveness?
This question evaluates experimental design, causal inference, statistical power/sample-size calculation, and marketing measurement competencies relev...
Estimate one-child household probability
You survey 100 children at a school and ask how many children are in their family. The responses are: - 50 children say their family has 1 child. - 20...
Build a cohort dashboard with Streamlit and SQL
You are given three tables and asked to build a minimal Streamlit app that helps a PM explore weekly cohort retention and ARPU by country. Assume SQL ...
Process real-time enter/exit events and actives
You receive a real-time stream of events with schema: user_id (str), channel (str), event_type ("enter"|"exit"), ts (UTC ISO timestamp). A user can ‘e...
Describe ownership in ambiguous, messy data work
Prepare behavioral answers for a remote Product/Risk Data Scientist role. Address these prompts with concrete examples: 1. Tell me about a time data c...
Predict Seller Intent From Subscription Data
You are given a take-home dataset, seller_intent_take_home_dataset.csv, containing about 5,000 new subscription records from a website-building platfo...
Write SQL for 30-day activity and D7 retention
You are given two tables. Table: trades - user_id (BIGINT) - trade_time (TIMESTAMP) — timestamp of the trade - volume (NUMERIC) - asset (TEXT) Table: ...
Find Top-5 Similar Rows
This question evaluates pairwise similarity matching, numerical feature comparison using mean squared error, null-value exclusion, and deterministic t...
Clean and Merge Housing Data
This question evaluates data cleaning, type coercion, robust merge operations, and missing-data imputation skills within tabular datasets, emphasizing...