A recent survey showed that students in the junior high school of the Normal University are more fascinated by roller skating than any other game, and the survey found that the average academic performance of students who often play roller skating is better than other students. , Playing roller skating can improve students' academic performance. Which of the following, if true, would most weaken the above inference? ["The affiliated middle school of the Normal University has signed an agreement with the parents of the students. If the child's academic performance is not ranked in the top 20, the two parties jointly prohibit the students from playing roller skating.", 'Playing roller skating can exercise and ensure the improvement of learning efficiency.', 'The students who played roller skating received effective guidance from the school, and some of them did not waste their studies.', 'Playing roller skating helps intellectual development and thus improves academic performance.']