Caffeinated Math
Interactive calculators, explorations, and mobile apps that show every step. Learn math by doing.
Mobile Apps
Run R directly on your mobile device using webR technology. Available on iOS and Android.
U.S. Citizenship Test Prep
Study for your naturalization interview with all 128 civics questions for the 2025 test.
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PocketShineComing Soon
Run Shiny for R and Python on your mobile device using Shinylive. Interactive web apps, no server required.
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Recently Added
Explore all →ARIMA Model Family
ExplorationUnderstand ARIMA(p,d,q) — how autoregressive, differencing, and moving average components combine
Time Series
GARCH Volatility Models
ExplorationExplore time-varying variance, volatility clustering, and the news impact curve
Time Series
Kalman Filter
ExplorationOptimal state estimation from noisy observations — balance model trust vs data trust
Time Series