Please read the article "Peer-reviewed report on Moderna COVID-19 vaccine publishes".

LINK: https://www.nih.gov/news-events/news-releases/peer-reviewed-report-moderna-covid-19-vaccine-publishes

Answer these questions:

(a) Was this clinical trial an observational study or an experiment? How do you know?

(b) What is the sample?

(c) What is the population?

(d) What are the treatments? (Hint: There are two.)

(e) The clinical trial used a placebo. Why do you think the researchers needed to use a placebo?

(f) Can we conclude that the Moderna COVID-19 vaccine (mRNA-1273) actually prevents symptomatic COVID-19? Explain.