In the formulas below, we will presume that we have a
random variable 5.2.1 \(X\) which maps the sample space S onto some range of real numbers
\(R\text{.}\) From this set, we then can define a probability function
\(f(x)\) which acts on the numerical values in
\(R\) and returns another real number. We attempt to do so to obtain (for discrete values) P(sample space value s)
\(= f(X(s))\text{.}\) That is, the probability of a given outcome s is equal to the composition which takes s to a numerical value x which is then plugged into f to get the same final values.