So far in hypothesis testing, we have been concerned mostly with single tests:
We also looked at comparisons among multiple groups with categorical data. Now, we move on to comparisons among multiple groups for continuous numeric data. When we want to compare more than two groups at a time, we use a technique known as analysis of variance, or ANOVA. The technical details of ANOVA, and especially the hypothesis testing, will be of interest mainly to the research community. However, data scientists who analyze multigroup experiments will find the graphical exposition and the discussion of variance decomposition of benefit.
After completing this chapter, you should be able to
Although the following data dates back to 1935, the purpose of the study—the amount of fat in our diet—is ...