Principles of Epidemiology in Public Health Practice: An Introduction to Applied Epidemiology and Biostatistics (38 mins)
Scroll down to "Lesson Three: Measures of Risk" and read pages 3-38 to 3-42 and 3-44 to 3-50. Complete Exercises 3.7 and 3.8. Once you are familiar with the material, complete questions 11 to 16, 23, and 24 in the 'Self-Assessment Quiz' on pages 3-55 to 3-60.
Click https://web.archive.org/web/20230519060949/https://www.cdc.gov/csels/dsepd/ss1978/SS1978.pdf link to open resource.