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 12.9 seconds. To test the difference of means she re-randomized the data 54 times, and the differences are plotted in the dot plot below. What can Erin conclude from her study?

A dot plot is shown labeled from negative 2.5 to positive 2. Above the negative 2.5 are 3 dots. Above the negative 2 are 6 dots. Above the negative 1.5 are 9 dots. Above the negative 1 are 12 dots. Above the negative 0.5 are 6 dots. Above the 0.0 are 4 dots. Above the 0.5 are 3 dots. Above the 1.0 are 7 dots. Above the 1.5 are 3 dots. Above the 2.0 is 1 dot.