On watching this video, students should be able to: Distinguish between an observational and experimental study. Explain the main reason why a randomised experiment can if done well, be used as a test ...

On watching this video students should be able to: List different types of observational study. Discuss the hierarchy of evidence tool. Explain why an observational study can generally only be used to ...

Americans who drank coffee in the morning had a lower overall mortality compared with those who drank coffee later in the day ...