Binomial Wahrscheinlichkeit RechnerFormel

## How to Calculate Binomial Probability

### Formula

**P(X = k) = C(n,k) * p^k * (1-p)^(n-k)**

The binomial distribution models the number of successes in n independent trials, each with the same probability p. C(n,k) counts the number of ways to arrange k successes among n trials. The mean is np and the variance is np(1-p).

Lösungsbeispiel

Flip a fair coin 10 times. What is the probability of exactly 3 heads?

  1. C(10,3) = 10! / (3! * 7!) = 120
  2. p^k = 0.5^3 = 0.125
  3. (1-p)^(n-k) = 0.5^7 = 0.0078125
  4. P(X=3) = 120 * 0.125 * 0.0078125 = 0.1171875
  5. Expected value = 10 * 0.5 = 5