To determine if watching television violence and playing violent video games cause children to act more aggressively, which research study would one conduct?

Randomly assign some children to play educational games and some to play violent games and they observe and record violent behaviors in them. The children assigned to educative game will be the control group while those assigned to violent games will be the treatment group. The null hypothesis for this study is that violent video games does not cause aggressive behaviors while the alternative hypothesis will be, violent video games cause aggressive behaviors.