In this topic, rather than testing for differences in means as we did via \(t\)-tests and ANOVA, we will be considering hypothesis tests for proportions. The types of questions that can be addressed with these types of tests include: is the proportion of left-handed people different from 10%? Or, has a particular intervention led to a significant difference in the proportion of premature births? Or, is the proportion of extroverts different from 50%?

As usual, we do not need to calculate the true population proportions to answer these questions. Rather, we can use sample data to calculate sample proportions, and then use these estimates to carry out hypothesis tests in order to draw inferences about the population proportions.