A scientist is evaluating the effectiveness of two new medicated ointments for skin rashes (Brand X and Brand Y). As a first step, the study tested the ointments on 21 patients with a chronic skin rash. Which scenario will tell the scientist more about the ointments? A Give 30 patients Brand X and 30 patients Brand Y, then after one week switch the medications for each group. B Give the 60 patients one brand, observe the results, and then give them the other brand
and observe the results. C Give 30 patients Brand X and 30 patients Brand Y. D Give 20 patients Brand X, 20 patients Brand Y, and 20 patients a cream containing no
medication.