Probability Mass Function

Used in the context of discrete Random Variable. The p.m.f. helps us understand how does the r.v. behave.

title: Probability Mass Function (Definition)
$f(x)$ is the [[Probability Mass Function|p.m.f.]] of $X$ if $f(x) = P(X = x)$.

See PDF for Continuous Random Variable.

Ex: Roll a die twice. = sum of the faces. Find the p.m.f. of :


Suppose is an r.v. with p.m.f. , then

pmf to cdf: