During the development of the COVID vaccine, researchers utilized two groups of participants. One group received the vaccine, while the second (control) group received a placebo. Rates of disease were compared between the two groups.

Is this study descriptive or analytic? (I believe it could be both...?)

What is the most likely research design used in this study? (examples - experimental, cross-sectional, retrospective cohort, prospective cohort, case control, case report, clustering)

What statistical tests would you expect to use in this research study? (examples - Incidence, prevalence, risk ratio, odds ratio, Cronbach alpha, paired t-test, power analysis, proportion)