150 Most Frequently Asked Questions On Quant Interviews ❲Quick – 2027❳

These questions assess your ability to think on your feet. The goal isn't always the "right" answer, but the logical path you take to get there.

You cannot avoid calculus. For junior roles, it’s about derivatives and integrals. For PhD-level roles, expect ODEs/PDEs and matrix decompositions.

| # | 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 | 150 Most Frequently Asked Questions On Quant Interviews

Final round with the head of the desk, Priya.

Priya: "You’re market making a stock at bid $10.00, ask $10.05. A buy market order comes in. You sell at $10.05. How do you hedge?" These questions assess your ability to think on your feet

Alex: "I’d short the stock at $10.05 to delta-neutral, then adjust based on my inventory. If I have positive gamma from options, I’d hedge dynamically."

Priya: "The stock then drops to $9.95. You lose $0.10 on the stock hedge but made $0.05 on the spread. Net –$0.05. Why not just avoid the trade?" You cannot avoid calculus

Alex: "Because over many trades, the spread is positive expectancy. The loss is inventory risk, which I can hedge further with options or futures."

Priya: "So why you? Why not a pure math major?"

Alex leans in. "Because physics taught me to model uncertainty with differential equations – but finance taught me that the real skill is knowing when your model is wrong. The 150 questions get you in the door. Not panicking when the model breaks gets you the job."

Priya extends her hand. "We’ll call you."