ベイズの定理計算機

共有リンク

はじめに

Bayes' Theorem Calculator — Apply Bayes' theorem to compute a posterior probability. Enter P(B|A), P(A), P(B) to get an instant, accurate result.

計算式

Bayes' theorem: P(A|B) = P(B|A) × P(A) / P(B), updating the prior probability P(A) using new evidence B.

ステップごとの説明

Enter the P(B|A).
Enter the P(A).
Enter the P(B).
Click Calculate to see your result instantly.

実例

Example: With P(B|A) = 0.9, P(A) = 0.01, P(B) = 0.1, the Bayes' Theorem Calculator gives P A Given B: 0.09.

よくある質問

What do the terms in the formula represent?

P(A) is the prior probability of A, P(B|A) is the likelihood of the evidence given A, P(B) is the overall probability of the evidence, and P(A|B) is the resulting posterior probability.

What is Bayes' theorem used for?

Common applications include medical test accuracy, spam filtering, and any situation where you need to revise a probability estimate in light of new evidence.

What inputs does the Bayes' Theorem Calculator need?

You'll need to provide: P(B|A), P(A), P(B). All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.

How accurate is the Bayes' Theorem Calculator?

The Bayes' Theorem Calculator applies the formula exactly as calculated — Bayes' theorem: P(A|B) = P(B|A) × P(A) / P(B), updating the prior probability P(A) using new evidence B. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.

Is the Bayes' Theorem Calculator free to use?

Yes, the Bayes' Theorem Calculator is completely free, requires no signup, and runs instantly in your browser.