| Sharpe Ratio Computation | easy |
| Moving Average Crossover Signal | easy |
| Z-Score Percentile | easy |
| Exponential Waiting Time | easy |
| Confidence Interval for Mean | easy |
| OLS Coefficient Interpretation | easy |
| T-Test for Mean (z-approximation) | medium |
| Pearson Correlation | medium |
| Simple Linear Regression | medium |
| MLE for Exponential | medium |
| KL Divergence | medium |
| Bivariate Normal Conditional | hard |
| GARCH Volatility Forecast | hard |
| Chi-Squared Goodness of Fit | medium |
| Ridge Regression Coefficients | hard |
| AR(1) Forecast | medium |
| Sharpe Ratio Significance | medium |
| Shannon Entropy | easy |
| Law of Large Numbers Intuition | easy |
| CLT Applied to Dice Sums | medium |
| P-Value Interpretation | easy |
| Type I and Type II Errors | easy |
| Regression to the Mean | medium |
| R-Squared Interpretation | easy |
| Maximum Likelihood Estimate for Coin Bias | medium |
| Variance of the Sample Mean | easy |
| Chebyshev's Inequality | medium |
| Covariance of X and X+Y | easy |
| Exponential Distribution Memoryless Property | medium |
| Correlation Does Not Imply Causation | easy |
| Moment Generating Functions Basics | medium |
| Bayesian vs Frequentist Coin | medium |
| Regression Coefficient Swap | medium |
| Testing if Correlation is Significant | medium |
| Beta-Binomial Posterior | easy |
| Normal-Normal Conjugate Update | medium |
| Bayesian Coin Identification | medium |
| PCA of Two-Asset Returns | medium |
| Minimum Components for Target Variance | easy |
| Half-Life of Mean Reversion | easy |
| Sample Autocorrelation | medium |
| GARCH Multi-Step Forecast | medium |
| GARCH Persistence and Shock Half-Life | easy |
| Ridge Shrinkage of a Regression Coefficient | medium |
| Look-Ahead Leakage in Cross-Validation | medium |
| Momentum Z-Score Signal | easy |
| Bonferroni Correction for Multiple Tests | easy |
| Benjamini-Hochberg FDR Rejections | medium |
| Expected Best-of-N Statistic and Data Snooping | medium |
| Statistical Power of a One-Sample Mean Test | medium |
| False-Positive Inflation from Peeking | easy |
| Mann-Whitney U Statistic | medium |
| Sign Test Exact P-Value | medium |
| Two-Sample Kolmogorov-Smirnov Statistic | medium |
| Unit Roots, Stationarity, and the ADF Test | medium |
| Paired T-Test Statistic | medium |
| Bayes Factor for Two Simple Hypotheses | medium |
| Gamma-Poisson Conjugate Update | medium |
| Mahalanobis Distance of a Return Vector | medium |
| Ideal Bootstrap Standard Error of the Mean | medium |
| Probability an Observation Is Left Out of a Bootstrap Sample | easy |
| Tail Dependence of a Student-t Copula | hard |
| Confidence Interval for a Proportion (Wald) | easy |
| Confidence Interval for a Variance (Chi-Square) | medium |
| Simulating Correlated Returns with Cholesky | medium |
| Variance Inflation Factor from Predictor Correlation | easy |
| Sample Size for a Two-Proportion A/B Test | medium |
| Two-Sample T-Test (Pooled, z-approximation) | medium |
| Hill Estimator of the Tail Index | medium |
| Peaks-Over-Threshold VaR with a Generalized Pareto Tail | hard |
| Chi-Square Test of Independence | medium |
| Why the Naive Bootstrap Fails on Returns | medium |
| Ljung-Box Autocorrelation Test | medium |
| Jackknife Estimate of Bias and Variance | medium |
| James-Stein Shrinkage Toward the Grand Mean | hard |
| Cramer-Rao Lower Bound from Fisher Information | hard |
| Welch's t-Test - Satterthwaite Degrees of Freedom | medium |
| Delta Method: Variance of a Nonlinear Transform | medium |
| Tukey HSD Critical Difference for Pairwise Means | medium |
| Hodges-Lehmann Estimator from Pairwise Averages | medium |
| Bias-Variance-MSE Decomposition of a Shrinkage Estimator | medium |
| Likelihood-Ratio Test for Nested Models | medium |
| Cohen's d Effect Size from Two Sample Means | easy |
| F-Test for the Equality of Two Variances | medium |
| Durbin-Watson Statistic for First-Order Residual Autocorrelation | medium |
| Levene's Test Statistic for Equality of Variances | medium |
| Kendall's Tau-b from Concordant and Discordant Pairs | medium |
| Hotelling's T-Squared - Two-Sample Multivariate Mean Test | hard |
| Anderson-Darling Statistic for a Normality Test | medium |
| Spearman Rank Correlation from Paired Observations | easy |
| One-Way ANOVA: F-Statistic from Between- and Within-Group Variation | medium |
| Benjamini-Hochberg: Largest Significant P-Value | medium |
| Mann-Whitney U from Rank Sums | medium |
| McNemar's Test for Paired Binary Outcomes | medium |
| Wilcoxon Signed-Rank Test Statistic | medium |
| Bhattacharyya Distance Between Two Gaussians | medium |
| Cochran's Q Test for Repeated Binary Outcomes | medium |
| Permutation Test P-Value for a Two-Sample Mean Difference | medium |
| Newey-West HAC Long-Run Variance for Autocorrelated Errors | hard |
| Bayesian Credible Interval with a Conjugate Normal Prior | medium |
| Sequential Probability Ratio Test Decision Boundaries | hard |
| BCa Bootstrap Bias-Correction Constant z0 | hard |
| AIC vs BIC Model Selection from Log-Likelihoods | medium |
| Cook's Distance for an Influential Regression Point | medium |
| Normal Tolerance Interval Covering a Population Proportion | hard |
| Grubbs' Test for a Single Outlier | medium |
| Partial F-Test for a Block of Regression Predictors | medium |
| Clopper-Pearson Exact Confidence Interval for a Proportion | medium |
| Method of Moments Estimates for a Gamma Distribution | medium |
| Fisher's Exact Test P-Value for a 2x2 Table | medium |
| Mantel-Haenszel Common Odds Ratio Across Strata | hard |
| Point-Biserial Correlation Between a Binary and Continuous Variable | easy |
| Kruskal-Wallis H Statistic for Several Groups | medium |
| Cramer's V Effect Size from a Contingency Table | easy |
| Wilson Score Interval for a Binomial Proportion | medium |
| Detecting a Non-Random Missingness Mechanism | easy |
| Pinball Loss and the Optimal Quantile Forecast | medium |
| Partial Correlation Controlling for a Third Variable | easy |
| Rao-Blackwell Variance Reduction via a Sufficient Statistic | hard |
| Friedman Test Statistic for Repeated-Measures Blocks | medium |
| Bartlett's Test for Homogeneity of Variances | medium |
| Theil-Sen Robust Slope from Pairwise Medians | medium |
| Exact Confidence Interval for a Poisson Rate | medium |
| Posterior Probability an Arm Is Best in Bayesian A/B | medium |
| EM Responsibility for a Two-Component Gaussian Mixture | medium |
| Kaplan-Meier Survival Probability with Censoring | medium |
| Intraclass Correlation Coefficient for Rater Reliability | hard |
| Cohen's Kappa for Inter-Rater Agreement | easy |
| Wald-Wolfowitz Runs Test for Randomness | medium |
| Empirical Bayes Shrinkage of Binomial Success Rates | hard |
| Jeffreys Prior Binomial Interval | medium |
| G-Test: Likelihood-Ratio Goodness of Fit | medium |
| Dunnett's Test for Comparing Treatments to a Control | medium |
| Omega-Squared Effect Size for ANOVA | medium |
| Exact Two-Sided Binomial Test P-Value | easy |
| Tukey Biweight Robust Location Estimate | hard |
| Breusch-Pagan Test for Heteroskedasticity | medium |
| Jarque-Bera Test for Normality from Skewness and Kurtosis | medium |
| Mallows' Cp Model Selection Criterion | medium |
| Gelman-Rubin R-hat Convergence Diagnostic | medium |
| Deming Regression Slope with Errors in Both Variables | hard |
| Hosmer-Lemeshow Calibration Statistic | hard |
| Jonckheere-Terpstra Ordered-Trend Test | hard |
| Box-Cox: Optimal Power Transform Lambda | hard |
| Winsorized Mean as a Robust Location Estimator | easy |
| Tukey Fences: IQR-Based Outlier Detection | easy |
| Dixon's Q Test for an Outlier in a Small Sample | medium |
| McFadden's Pseudo R-squared from Deviance | medium |
| Harrell's C-Index: Concordance of a Risk Score | medium |
| Huber M-Estimator: Per-Observation Influence Weights | hard |
| White's Test for Heteroskedasticity | medium |
| Shapiro-Wilk W Statistic for Normality | medium |
| Effective Sample Size of an Autocorrelated Chain | medium |
| Laplace Rule of Succession Prediction | easy |
| Tweedie's Formula for the Posterior Mean | hard |
| Gini Coefficient from a Discrete Distribution | medium |
| Somers' D Rank Association | medium |
| Brier Score for Probabilistic Forecast Accuracy | easy |
| Holm-Bonferroni: Step-Down Rejection Count | medium |
| Negative Binomial Overdispersion vs Poisson | medium |