Chapter 25 Section 5.2: Comparing Several Population Means
In the previous section, you learned the chi-squared test for comparing proportions among two or more groups. One key point was that there are advantages to an overall procedure that compares the proportions simultaneously and controls the overall Type I error rate. When there are only two groups, this procedure was equivalent to the two-sided two-sample z-test for proportions. You will see a similar approach in this section, addressing the issue of comparing two or more population means. The technique you learn here will be used both for comparing population means based on independent random samples and also for assessing whether there is a treatment effect based on data from a randomized experiment.
