確率計算機

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はじめに

Probability Calculator — Independent events: both, either, neither. Enter P(A), P(B) to get an instant, accurate result.

計算式

P(both) = P(A)×P(B). P(either) = P(A)+P(B)−P(both). P(neither) = (1−P(A))×(1−P(B)) — assumes A and B are independent.

ステップごとの説明

1. Enter the P(A).
2. Enter the P(B).
3. Click Calculate to see your result instantly.

実例

Example: With P(A) = 0.5, P(B) = 0.3, the Probability Calculator gives Both: 0.15, Either: 0.65, Neither: 0.35.

よくある質問

Does this assume A and B are independent?

Yes — these formulas only hold when the two events don't influence each other.

What is "P(either)"?

The probability that at least one of the two events occurs.

What inputs does the Probability Calculator need?

You'll need to provide: 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 Probability Calculator?

The Probability Calculator applies the formula exactly as calculated — P(both) = P(A)×P(B). P(either) = P(A)+P(B)−P(both). P(neither) = (1−P(A))×(1−P(B)) — assumes A and B are independent. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.

Is the Probability Calculator free to use?

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

確率計算機について

The Probability Calculator uses a real, verifiable formula — P(both) = P(A)×P(B). P(either) = P(A)+P(B)−P(both). P(neither) = (1−P(A))×(1−P(B)) — assumes A and B are independent. — so results are accurate every time, not an approximation.