A Distribution Tables

A.1 Discrete Distributions

Distribution of X f(x) Support E[X] Var[X]
Hypergeometric(n,N1,N0) \displaystyle \frac{\binom{N_1}{x} \binom{N_0}{n-x}}{\binom{N}{n}} x=0, 1, \ldots, n n \frac{N_1}{N} n \frac{N_1}{N} \frac{N_0}{N} \left(1 - \frac{n-1}{N-1}\right)
Binomial(n, N_1, N_0) \displaystyle \frac{\binom{n}{x} N_1^x N_0^{n-x}}{N^n} x=0, 1, \ldots, n n \frac{N_1}{N} n \frac{N_1}{N} \frac{N_0}{N}
Binomial(n, p) \binom{n}{x} p^x (1-p)^{n-x} x=0, 1, \ldots, n np np(1-p)
Geometric(p) (1-p)^{x-1} p x=1, 2, \ldots \frac{1}{p} \frac{1-p}{p^2}
NegativeBinomial(r, p) \binom{x-1}{r-1} (1-p)^{x-r} p^r x=r, r+1, \ldots \frac{r}{p} \frac{r(1-p)}{p^2}
Poisson(\mu) e^{-\mu} \frac{\mu^x}{x!} x=0, 1, 2, \ldots \mu \mu

A.2 Continuous Distributions

Distribution of X f(x) Support E[X] \text{Var}[X]
Uniform(a, b) \frac{1}{b-a} a < x < b \frac{a+b}{2} \frac{(b-a)^2}{12}
Exponential(\lambda) \lambda e^{-\lambda x} 0 < x < \infty \frac{1}{\lambda} \frac{1}{\lambda^2}
Gamma(r, \lambda) \frac{\lambda^r}{(r-1)!}x^{r-1} e^{-\lambda x} 0 < x < \infty \frac{r}{\lambda} \frac{r}{\lambda^2}
Normal(\mu, \sigma) \frac{1}{\sigma\sqrt{2\pi}} e^{-\frac{(x - \mu)^2}{2\sigma^2}} -\infty < x < \infty \mu \sigma^2