Consider the following 3 scenarios.

1. Researchers wish to investigate a possible effect of caffeine on athletic

performance.

II. Researchers wish to investigate a possible relationship between embezzlement

and alcohol use.

III. Researchers wish to investigate a possible relationship between a daily intake of

pomegranate juice and sleep quality.

Which of these scenarios would best be carried out as an experiment rather than an

observational study or survey?

Just I.

I and II.

I and III.

II and III.

All of them.