TOPIC 21

Comparing Two Proportions

Can swimming with dolphins help depression patients recover from their symptoms? How can a randomized experiment help us decide? Did the proportion of babies who slept on their stomachs decrease between 1992 and 1996? How would collecting data for such a study be different from collecting data for the dolphin study? How do we analyze the results? How do both of these studies differ from those in Unit 4? In this topic, you will learn how to apply the inference principles that you learned in the previous unit to address questions of comparisons of two groups.