## Overview

Bayes’ theorem is today considered one of the main theorems in statistics, and one of the most applied formulae in science.

its importance grew steadily until the middle of the last century. And it is now considered essential in all statistics courses, and applied in almost every field of research and not least in Bioinformatics, where it has been applied extensively to the biological system analysis.

At first glance, Bayes’ theorem can seem confusing, counterintuitive, and hard to grasp. We know that, for many, statistics is not intuitive, as with other aspects of mathematics.

However, if we analyse the thought processes leading Bayes to his theorem, we see that these are natural and logical ways of thinking.