Principles of Hypothesis Testing

You have already learned how to estimate an unknown population value with a confidence interval. But often we face a sharper question: “Does this new teaching method actually improve test scores?” or “Is this coin fair?” Hypothesis testing gives us a logical, step‑by‑step method to answer such yes/no questions using data. In this chapter we will build that method from the ground up. By the end, you will see why a test and a confidence interval are really two sides of the same coin.