A study is designed to evaluate the impact of a daily multivitamin on students’ academic performance. One hundred sixty students are randomly assigned to receive either the multivitamin or a placebo...

A study is designed to evaluate the impact of a daily multivitamin on students’ academic performance.  One hundred sixty students are randomly assigned to receive either the multivitamin or a placebo and are instructed to take the assigned drug daily for 20 days.  On day 20, each student takes a standardized exam and the mean exam scores are compared between groups.

Identify what type of study this is.