Erin wants to know if warming up will help runners sprint faster. Twenty-six track and field athletes volunteered to participate in her study. She randomly assigns 13 athletes to warm-up for 10 minutes. All 26 participants sprint the same distance. She calculates the mean for each group and determines that the mean for the warm-up group was 10.9 seconds and the mean for the other group was 13.9 seconds. To test the difference of means, she re-randomized the data 250 times and the differences are plotted in the dot plot below. What can Erin conclude from her study?

Question