The last group served as the control group and was put on a low - fat diet. (dietselfhelp.com)
We do so by randomly assigning interventions that provide different types of information to roughly 18,000 students, including 3,000 students who serve as controls. (educationnext.org)
Half of them were randomly selected for the intervention described above, while the other half served as a control group. (edutopia.org)