150 Most Frequently Asked Questions On Quant Interviews -

| # | Question | Difficulty | Key Idea | |---|----------|------------|-----------| | 56 | What is the difference between correlation and causation? | ★ | Example: ice cream sales and drowning | | 57 | What is a p-value? | ★ | P(data | null) | | 58 | Explain bias-variance tradeoff. | ★★ | Underfitting vs overfitting | | 59 | What is MLE? Give example for normal distribution. | ★★ | Sample mean is MLE for μ | | 60 | You have i.i.d. N(μ,1). Find 95% CI for μ. | ★ | x̄ ± 1.96/√n | | 61 | What is a consistent estimator? | ★ | Converges in probability to true value | | 62 | What is the Central Limit Theorem? | ★ | Sum of i.i.d. → normal | | 63 | You have two samples. Test if means equal. Which test? | ★ | t-test | | 64 | What is the difference between parametric and nonparametric tests? | ★ | Distribution assumption | | 65 | What is a Type I error? Type II? | ★ | False positive, false negative | | 66 | What is power of a test? | ★ | 1 – P(Type II) | | 67 | What is the standard error of the mean? | ★ | σ/√n | | 68 | What is a confidence interval? | ★ | Range containing true parameter with certain probability | | 69 | What is a chi-square test used for? | ★ | Goodness of fit, independence | | 70 | What is the difference between regression and classification? | ★ | Continuous vs categorical output | | 71 | What is overfitting? How to detect? | ★ | High train, low test performance | | 72 | What is cross-validation? | ★★ | K-fold | | 73 | What is regularization? L1 vs L2? | ★★ | Lasso vs Ridge | | 74 | What is a sufficient statistic? | ★★ | Contains all info about parameter | | 75 | What is the Cramér-Rao lower bound? | ★★★ | Lower bound on variance of unbiased estimator | | 76 | You have data with outliers. Robust estimator for mean? | ★ | Median | | 77 | What is the difference between likelihood and probability? | ★ | Likelihood = P(data | parameter) | | 78 | What is the Law of Large Numbers? | ★ | Sample mean → population mean | | 79 | What is the difference between correlation and covariance? | ★ | Correlation is normalized covariance | | 80 | How do you test if a coin is fair? | ★ | Binomial test |

The key isn't just rote memorization; it is about decomposition. For $24 \times 27$, a quant candidate might think: $24 \times 25 = 600$, plus $24 \times 2 = 48$. Total: 648. You are expected to know your squares up to at least 20 and your prime numbers up to 100. 150 Most Frequently Asked Questions On Quant Interviews

Never neglect the human element. You will likely be asked to describe a time you failed, why you want to work for that specific firm, and how you handle conflict in a team. Strategic Preparation Tips | # | Question | Difficulty | Key

"150 Most Frequently Asked Questions on Quant Interviews" by Stefanica, Radoičić, and Wang is a comprehensive, third-edition guide tailored for quantitative finance roles, covering topics from mathematics to machine learning. Designed for interview prep, the book offers concise, technical solutions to questions in areas like C++ programming, financial instruments, and brainteasers. Explore the guide and its sample questions on the Financial Engineering Press website Amazon.com

Alex visualizes: Fill the 5, pour into 3 → leaves 2 in the 5. Empty the 3, pour the 2 from 5 into 3. Fill the 5 again, pour 1 gallon into the 3 (which already has 2) → leaves 4 in the 5.

: Riddles designed to test your ingenuity under pressure, such as the "manhole cover" logic or "light switch" puzzles.