probability generating function
The mean and variance of X can also be computed using the pgf from
The pgf of the sum X + Y of two independent random variables is given by
and for random sampling, where Z = X1 + … + XN, with N itself a random variable and the Xi are iid, then 
- Playfair's axiom
- plot
- plus
- Plus magazine
- plus or minus
- plus sign
- pmf
- p-norm
- Poincaré group
- Poincaré-Hopf theorem
- Poincaré, (Jules) Henri
- point
- point estimate
- point mass
- point of application
- point of inflexion
- points at infinity
- point-set topology
- pointwise addition
- pointwise convergence
- Poisson distribution
- Poisson process
- Poisson's equation
- Poisson, Siméon-Denis
- Poisson's integral formula