Treatment
The treatment comprised of two parts: lecture and worksheet. Initially, the author delivered a common lecture to both treatment groups. The lecture occurred simultaneously to both groups to prevent the effect of any extraneous variables such as time of day, day of week, lighting of room, and others. The lecture was 50 minutes in length. It was based on series dc circuits and parallel dc circuits. Next, one section was randomly assigned to the "individual learning group" while the other section was assigned to the "collaborative learning group". The two sections worked in separate classrooms.