Statistics & Finance
Statistics and finance tools - distributions, probability, inference, compound growth, and investment models.
Probability Distributions
- Binomial Distribution Explorer — Explore P(X = k) and cumulative probabilities for binomial trials.
- Central Limit Theorem Explorer — Simulate how sample means converge toward a normal distribution for uniform, exponential, and bimodal sources.
- Confidence Interval Calculator — Calculate confidence intervals for means and proportions with margin of error.
- Kanji Frequency & Probability Explorer — Explore Japanese kanji frequency, cumulative reading coverage, encounter probability, and stroke-count statistics — statistics and probability applied to written Japanese.
- Normal Distribution Explorer — Explore the bell curve: set mean and standard deviation with sliders, shade a region between x1 and x2, and calculate the probability live.
- Poisson Distribution Explorer — Visualize Poisson PMF/CDF with Binomial convergence overlay and interactive parameter exploration.
- Z-Score Calculator — Compute z-scores, percentiles, and convert z back to raw values.
Statistical Tests & Modeling
- Causality Sandbox — Compare causal, confounded, collider, and Simpson scenarios to see why correlation can mislead.
- Chi-Square and Residual Map — Edit contingency tables and inspect expected counts, standardized residual heatmaps, and chi-square contributions.
- Linear Regression — Fit a least-squares line to your data with scatter plot, residuals, Pearson r and Spearman ρ.
- Student's t-Test — One-sample and two-sample Welch t-test with t-distribution curve and rejection region visualization.
- SVD Decomposition Explorer — Explore singular values, low-rank reconstruction, kept energy, and why SVD matters for compression and denoising.
Probability Paradoxes & Demos
- Bayes Theorem / False Positive Explorer — Explore Bayes theorem with prevalence, sensitivity, and specificity to understand false positives.
- Birthday Paradox Explorer — Explore how quickly shared-birthday probability rises with group size.
- Coincidence Cluster (Streak Paradox) — Coin-toss streak explorer: compare theoretical streak probability against Monte Carlo simulation.
- Combinatorics Workbench — Solve combinations, permutations, distributions, and classic counting constraints from one place.
- Deja-Vu Detector — See how often repeated local patterns appear in random symbol streams.
- Monte Carlo Pi Explorer — Estimate pi with random sampling.
- Queueing Theory Simulator (M/M/1) — Explore utilization and waiting time in M/M/1 queues.
- Sample Size & Margin of Error Planner — Plan sample size or margin of error from confidence level and expected proportion.
Finance & Economics
- Annuity Future Value — See how regular deposits compound into wealth over time — balance, contributions, and annual growth in one chart.
- Compound Interest Explorer — Explore compound growth with principal, rate, years, and compounding frequency. Compare standard compounding to continuous compounding on a live graph.
- Demography + Economics Lab — Interactive population-economy simulator with equation-driven insight and scenario decomposition.
- Inflation Adjuster — See how inflation erodes purchasing power and inflates nominal values over time.
- Linear Programming (2D) — Visualize constraints, feasible regions, and corner-point optimization in two dimensions.
- Loan Payment Calculator — Estimate monthly payment, total interest, and amortization schedule for fixed-rate loans.
- Markup vs Margin — Compare markup and margin from cost and selling price.
- Portfolio Diversification Check — See whether a portfolio is spread across assets that behave differently, using snapshot-based correlations and volatility.
- Simple vs Compound Interest — Compare final value under simple interest and compound interest for the same principal, rate, and horizon.
- Supply-Demand Shock Simulator — Shift supply and demand curves and observe equilibrium.