VastCalc
Statistics
Binomial Distribution Calculator
Calculate binomial probabilities P(X = k), P(X ≤ k), and P(X ≥ k) for a given number of trials, successes, and probability of success.

Binomial Distribution Calculator

Calculate binomial probabilities for a fixed number of independent trials. Find the probability of exactly k successes, at most k successes, or at least k successes.

The binomial distribution models the number of successes in n independent trials, each with probability p.

PMF (Probability Mass Function): P(X = k) = C(n,k) × p^k × (1-p)^(n-k)

Where C(n,k) = n! / (k!(n-k)!) is the binomial coefficient.

Key Properties:

  • Mean: E(X) = n × p
  • Variance: Var(X) = n × p × (1-p)
  • Standard deviation: σ = √(n × p × (1-p))

Examples:

  • Coin flips (p = 0.5)
  • Quality control defects
  • Survey yes/no responses

Frequently Asked Questions

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