An overview of hypothesis testing

To begin with the overview, I would like to share an ongoing example from while I was writing this book. As the coronavirus spread throughout the world, pharmaceutical and biotechnology companies worked around the clock to develop drugs and vaccines. Scientists estimated that it would take at least a year for a vaccine to be available. To verify the effectiveness and safety of a vaccine or drug, clinical trials needed to be done cautiously and thoroughly at different stages. It is a well-known fact that most drugs and vaccines won't reach the later trial stages and only a handful of them ultimately reach the market. How do clinical trials work? In short, the process of screening medicines is a process of hypothesis testing.

A hypothesis is just a statement or claim about the statistics or parameters describing a studied population. In clinical trials, the hypothesis that a medicine is effective or safe is being tested. The simplest scenario...