distribution formulas Flashcards
Conditions for binomial
fixed number of trials
independent of each other
constant probability of siuccess
two outcomes
Expectation and variance of binomial
E(X) = np
Var(X) = np(1-p)
conditions for poission
Random rate of occurcence
independent
uniform average rate of occurence
Expectation and variance of poission
Lambda for both
Formula for poission distribution
x !
conditions for the geometric
When there is a number of independent trials until a success is achieved
two outcomes
p(X=x) for geometric distribution
(1-p)x-1 x p
P(X <= x) For geometric
1 - (1 - p) x
expectation and variance
E(X) = 1 / P
Var(X) = 1 - p / p2
when to use uniform distribution
When there is an equally likely number of outcomes
Expectation and variance of a uniform distribution
E(X) = n + 1 / 2
Var(X) = ( n + 1)(n - 1) / 12
proof of uniform distribution expectation and variance
dede