# Bayes Tree Lab

> Bayes Tree Lab (iPhone/iPad app by Memnune Karatas.)

- Source: https://appshunter.io/ios/app/bayes-tree-lab/id6828436726 (this page in markdown: same URL + `.md`)
- Developer: [Memnune Karatas](https://appshunter.io/developer/6828436728)
- Category: Education
- Price: Free
- Age rating: 4+
- Requires: iOS 15.0 · 4 MB
- Languages: American English
- Released: 2026-11-05
- Data updated: 2026-11-06

## What is Bayes Tree Lab?

Bayes Tree Lab turns conditional probability into something you can see, edit, and check.
Build a two-stage probability tree, follow every path, and watch Bayes' theorem unfold one line at a time. Then run a seeded simulation and compare what the theory predicts with what actually happens. Every experiment can be saved and reopened later, so you can re-check your work whenever you like.
DRAW AND EDIT THE TREE
- A clear branch diagram with events A and not-A, then B and not-B.
- Edit the prior P(A) and the two conditional probabilities with a slider or by typing.
- Sibling branches rebalance automatically, so each pair always adds up to exactly one.
- Branch thickness follows probability, so large and small chances are easy to compare.
CHECK EVERY PATH
- See the joint probability of all four paths, with the multiplication written out.
- A built-in check confirms that the paths add up to one.
BAYES POSTERIOR, FULLY EXPANDED
- Choose whether you observed B or not-B.
- Follow three explicit steps: joint probabilities, evidence probability, and the posterior.
- Impossible cases, such as an observation with zero probability, are explained instead of hidden.
ODDS FORM
- See prior odds multiplied by the likelihood ratio to give the posterior odds.
- A log-odds axis shows how far the evidence moved your belief.
- The result is cross-checked against the standard Bayes posterior.
NATURAL FREQUENCIES
- View the same problem as head-counts in a population of 100, 1,000, or 10,000.
- A plain sentence shows how the posterior comes from simple counting.
SEEDED SIMULATION
- Enter a random seed and a number of trials, up to one million.
- The same seed and inputs always produce the same counts, so results are repeatable.
- Compare expected and observed counts for each path, with differences and relative error.
- A bar chart and a chi-square test show how well the simulation fits the theory.
SAVE, REOPEN, AND VERIFY
- Save any run together with its inputs, seed, and counts, plus an optional note.
- Reopen it from History at any time.
- Tap Re-run to verify to reproduce the run from its seed and confirm every count matches.
- Share a plain-text summary of a run with a classmate or teacher.
PRACTICE WITH CLASSIC PUZZLES
- Guess the answer to well-known base-rate problems such as medical screening, a taxi witness, a spam filter, and factory defects.
- Lock in your guess, then see the exact answer, how far off you were, and a simple head-count explanation.
- Open any puzzle on the tree to explore it further.
- Your best scores are tracked on your device.
BUILT FOR LEARNING
- Made for students, teachers, and anyone meeting conditional probability for the first time.
- Works offline. No account, no sign-in, no ads.
- Your data stays on your device. Bayes Tree Lab does not collect any personal information.
Questions or feedback? Contact us at support@bayestreelab.app.

## Is Bayes Tree Lab safe?

Not enough ratings yet to assess Bayes Tree Lab.

## Is Bayes Tree Lab legit?

Bayes Tree Lab has limited verification signals. The AppsHunter Legitimacy Score for Bayes Tree Lab is 50 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0 — 2026-11-05

No release notes.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-11-06.*