We will use the paired t-test statistical method to compare the pre-test and post-test scores for both groups. This approach will help us evaluate how aggression levels change based on the type of video game played. For this analysis, we will use Cohen's d to measure effect size, which shows the standardized difference between two means and helps us understand the practical importance of the findings. We will interpret effect sizes as follows: 0.2 for a small effect, 0.5 for a medium effect, and 0.8 for a large effect. This will allow us to assess the extent of differences in aggression levels between teenagers who play cooperative versus competitive video games