Jonathan, You provided a great definition of Hypothesis testing. One thing to remember is that when we collect data, we do so from a sample population rather than the entire population. For instance, let's consider a sample of 400 female students where 289 have blue eyes. It is important to note that our data is collected from the sample collection and not the entire population. It is not possible to collect data from the whole female population in a school due to several reasons such as absence, dropout, etc