02. Binomial

Use a binomial distribution when:

  • you test a random variable which is a boolean
  • you test this variable n times
  • you want to know the number of times it was True.

The binomial probability mass function of getting True exactly k times out of n tries is:

f(k):=\binom{n}{k}⋅p^k⋅(1-p)^{n-k}

(this again uses the mathematician's trick of avoiding decisions, see Bernoulli Distribution).

(this uses the variation counter explained in Variation).

Expected Value

E:=n⋅p

Variance

V:=n⋅p⋅(1-p)

Author: Danny (remove the ".nospam" to send)

Last modification on: Thu, 09 May 2013 .