Discrete Distributions
It is said that a random variable X has a discrete distribution or that X is a discrete random variable if X can take only a finite number k of different values or, at most, an infinite sequence of different values Random variables that can take every value in an interval are called continuous and are discussed in Section 3.2. If a random variable X has a discrete discrete distribution, the probability funcyion (abbreviated p.f) of X is defined as the function f such that for every real number x,
f(x)=Pr(X=x).