In section [2C], you learned about experimental studies, and in the preview assignment for this activity, you learned that observational studies are sometimes used when an experiment would be untenable or unethical to conduct. This Forming Connections activity should help you synthesize the ideas about experiments and observational studies that you seen so far. In particular, you’ll see that observational studies are different from experimental studies because confounding factors can create associations in observational studies in ways that shouldn’t occur in controlled experiments with random assignment. In this activity, you’ll use real world data to investigate what it means to conduct an observational study.

Effective Vaccines?

In the previous in-class activity, you learned about a type of statistical study known as an experimental study. However, it is not always appropriate to use experimental studies.

Work in pairs to discuss Question 1. As you do, you may wish to reflect on the example in the preview assignment in which the researcher wanted to explore how smoking habits relate to depression.