freeCodeCamp/guide/english/mathematics/binomial-distribution/index.md

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Binomial Distribution

If X ~ B(n,p) then: P(X=x) = (n/x)p^x multiplied by (1-p)^(n-x)

If X ~ B(n,p) then: E(X) = np Var(X) = np(1-p)

Binomial distributions only occur if:

• There's a fixed number of trials, n.
• Each trial should be either a success or failure.
• Probability of success (p) is constant at each trial.
• Independent trials.