The Different Distributions Flashcards
Conditions for Binomial Distribution
Fixed number of trials
Independent trials
Constant probability of success
Two outcomes
Binomial P(X=x)
nCr p^r (1-p)^n-r
Binomial Expected Value
E(X) = np
Binomial Variance
Var(X) = np(1-p)
Conditions for Poisson
Random events
Independent Events
Constant rate of occurring
Poisson P(X=x)
What can happen if you have two independent poisson distributions?
X + Y - Po(X1 +X2)
What can happen if your n is too large and p too small in binomial?
can turn into poisson distribution
Poisson Expectation
E(X) = λ
Poisson Variance
Var(X) = λ
Conditions for Geometric
only 1 successful outcome
Geometric P(X=x)
(1-p)^x-1 (p)
Geometric Expectation
E(X) = 1/p
Geometric Variance
1-p/ p2
Geometric P(X>x)
(1-p)^x
Geometric P(X<r)
1-(1-p)^x-1
Conditions for Discrete Uniform Distribution
fixed number of equally occuring trials
Uniform P(X=x)
1/n
Uniform Expectation
n+1 /2
Uniform Variance
(n+1)(n-1) / 12