To evaluate a new online algebra game, researchers recruited 120 ninth-grade volunteers from a single high school. The volunteers were randomly assigned to one of two groups:
- Game group (60 students): played the algebra game for 20 minutes each school day for 6 weeks.
- Control group (60 students): continued their usual math homework for 6 weeks.
At the end of the 6 weeks, the average end-of-unit test score of the game group was 8 points higher than that of the control group, and the difference was statistically significant.
Which conclusion is best supported by the design and results of this study?