After the great progress in the theory of probability as a science, the passage towards
more flexible and representative definitions and the possibility to be implemented numerically
gave the need for a new formulation. From there, the random variable came into existence.
Although random problems can be of different kinds, the random variable can be discrete or
continuous, qualitative or quantitative. This chapter is dedicated to its extended definition and
its exploitation in a simplified way.
Keywords: Bernoulli’s random variable, Probability law, Quantitative and qualitative random variables, Random variable, Types of random variables.