Researchers in Canada performed an experiment with university students to examine the effects of in-class laptop use on student learning. All volunteers in the study were asked to attend a university style lecture and take notes with their laptops. Half of the participants were assigned to complete other non-lecture related online tasks during the lecture. These tasks were meant to imitate typical student Web browsing during classes. The remaining students simply took notes with their laptops. To assign the treatments, the researchers printed 40 papers with instructions (20 with multitasking and 20 without), shuffled them, and handed them out at random to students in the classroom. At the end of the lecture, all participants took a comprehension test to measure how much they learned from it. The results: students who were assigned to multitask did significantly worse than students who were not assigned to multitask. What is the purpose of randomly assigning the students to treatments? A) To prevent non-response among the 40 volunteers.
B) Random assignment helps avoid bias to the placebo effect. Random assignment allows the researchers to generalize the results to all students.
C)To make sure that the study is double-blind.
D)To create groups of students that are roughly equivalent at the beginning of the study.