Thanks to the article from 1900 by Karl Pearson and, mainly, to the article from 1925 by Sir Ronald A. Fisher, we have adopted a mathematical way on testing our hypotheses. The key idea is to use probabilistic theories to quantify uncertainty/certainty in your claims. E.g the well-known chi-squared test or a t-test help with this. These theories are widely used in medicine, psychology, finance and many-many more. So this is what this course is about: to go through those theories, tests and applications. Note: like always we do at Quanta, we will take a rather fundamental approach and thus not leave you with "just use this formula". So not only we will see where it all comes from, we will actually open a whole spectrum of possible issues with the blind applications of the famous tests! But in any case, knowing these is a huge advantage in a job search or joining an interesting project to work on.