Upstart Interview Questions
Practice the exact questions companies are asking right now.
Implement four string-processing functions
You are given four independent string/list problems. Implement each as a separate function. 1) Filter strings by shared characters Input: - words: a l...
Implement factorial and count trailing zeros
Answer the following coding questions in Python. 1) Implement factorial Implement a function factorial(n) that returns \(n!\) for a non-negative integ...
Compute decay, OLS, and classic probability results
You are asked several probability/statistics questions. 1) Radioactive decay (half-life) A radioactive atom has a half-life of 1 day. Assume each atom...
Solve drunk-passenger probability and simulate outcome
Lost Boarding Pass Puzzle: Last Passenger's Seat Context: Technical screen for a Data Scientist (Statistics & Math). Setup - There are n passengers la...
Find max word letter span
Implement a function that, given an input text string, computes the maximum word letter span and returns both (a) the maximum span and (b) the list of...
Explain L1 vs L2 and ridge vs lasso
Explain the differences between: 1. L1 vs L2 regularization (how they change the objective, geometry/intuitions, and typical effects on learned parame...
Identify binomial model and compute moments
Tossing N Balls Into a Cup (Independent Hits with Probability p) You toss N independent balls toward a cup. Each ball lands in the cup with probabilit...
Combine noisy thermometers; compute random-walk correlations
Problem 1: Estimating a true temperature from noisy thermometers Assume the true (fixed) temperature is an unknown constant \(\theta\). 1a) One thermo...
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...
Implement PAVA spend-smoothing under no-borrowing constraint
Monotone Spending Plan via Isotonic L2 Regression (No-Borrowing) Context: You observe yearly discretionary income profit[1..65] (nonnegative reals) an...
Interpret A/B results with p-values and uncertainty
A/B Test: Effect Sizes, CIs, Multiple Testing, Power, and Decision Context: You ran a 14‑day experiment (2025‑08‑15 → 2025‑08‑28) with 1:1 allocation ...
Calculate Expected Streaks in Coin Toss Sequence
Expected Number of Streaks in Coin Tosses Scenario You toss a coin repeatedly. A "streak" (a run) begins on the first toss and whenever the current to...
Explain tackling ambiguity and defending a decision
Behavioral: Ambiguous Analytics With Incomplete Data and a Tight Deadline Context: You're a Data Scientist interviewing in a technical screen focused ...
Evaluate channels and allocate budget
Marketing Analytics Case: Funnel, Attribution, Budget Optimization, and Incrementality You are given a daily-by-channel dataset with the following col...
Decide to ship a signup experiment
A/B Test Plan: Redesigned User Signup Flow Context and Data You are analyzing an A/B experiment for a redesigned user signup flow. The dataset include...
Simulate Radioactive Decay to Validate Analytical Solution
Scenario Same radioactive-decay problem, but now validate the analytical answer via simulation during the interview. Question Share screen and write r...
Estimate Family Proportions and Explain Regression Anomalies
On-site Statistics Round Task Overview You are given a population of families that have either 1, 2, or 3 children. You sample 100 children (i.e., the...
Explain career moves and defend moat
Interview Prompt: Career Chronology, Competitive Advantage, and Exec Presentation Trade‑offs Context: You are interviewing for a Data Scientist role i...
Assess Probability of Heads in Coin Tosses
Probability with Coin Tosses and the Normal Distribution Context Onsite data scientist screening question assessing basic probability and distribution...
Estimate and Derive Regression Coefficient for X on y
Statistics & Probability Onsite — Two-Part Question Context - You have a simple linear data-generating process: y = X + ε, where X and ε are independe...