In an experimental study conducted by the NIH, the researchers control how long people stay on medication. Half of a sample of depressed people is randomly chosen to receive medication for less than six months; the others receive medication for more than six months. The only way the two groups differ is in the duration of the medication. One year after the start of treatment, all participants are asked to perform a survey regarding the number of major depressive episodes they have experienced in the past six months. The research hypothesis is that individuals who remain on depression medication for more than six months will experience fewer instances of major depressive episodes than individuals who stop treatment prior to six months. Will this research design allow the experimenters to properly test their hypothesis?