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