Distributions

Drag the curve. Shade a region. Watch probability respond.

Distributions is a modern statistics study tool for students, educators, and anyone who wants to feel how probability distributions behave—not just memorize formulas.

EXPLORE 41 DISTRIBUTIONS
Browse discrete and continuous families with interactive PDF/PMF and CDF charts, live parameter sliders, descriptive statistics, examples, and random sampling. Search, favorites, recents, and side-by-side comparison keep the catalog usable on iPhone and iPad.

TOUCH THE MATH
Drag parameters on the chart and see the shape move. Turn on Probability mode to shade continuous regions or select discrete values and read the probability instantly. Typeset formulas stay linked to the live parameters.

LEARN DEEPER
Practice with Guess-the-Distribution quizzes, walk a relationship map between families, look up a searchable glossary, and check live z, t, and χ² critical values—all offline.

ON-DEVICE AI (APPLE INTELLIGENCE)
Ask the Distribution Advisor to suggest a distribution from a scenario, tap Explain for contextual teaching prompts, and optionally mix AI-generated quiz questions. AI output is labeled and advisory; exact probabilities and quantiles always come from the app’s calculator. When Apple Intelligence is unavailable, Explain and quizzes use built-in content and the Advisor tells you why it’s unavailable—everything else works the same. No accounts. No tracking. No third-party AI services.

FIT MY DATA
Paste or import a dataset, estimate candidate distributions, rank goodness of fit, inspect histogram and Q–Q overlays, and export reports.

ONE-TIME PURCHASE
Distributions is a paid app. One purchase includes all 41 distributions, interactive charts, calculators, Fit My Data, saved parameter sets, every quiz mode, exports, and unlimited on-device Advisor use. No subscriptions. No in-app purchases. No ads.

Privacy-first by design: your exploration stays on your device.