Carter wants to know if warming up will help runners sprint faster. Thirty track and field athletes volunteered to participate in his study. He randomly assigns 15 athletes to warm-up for 10 minutes. All 30 participants sprint the same distance. He calculates the mean for each group and determines that the mean for the warm-up group was 10.7 seconds, and the mean for the other group was 13.2 seconds. To test the difference of means he re-randomized the data 54 times, and the differences are plotted in the dot plot below. What can Carter conclude from his study?
The graph shows: (3) -2.5, (6) -2.0, (9) -1.5, (12) -1.0, (6) -0.5, (4) 0.0, (3) 0.5, (7) 1.0, (3) 1.5, and (1) 2.0. The parenthesis is how many dots there is at each point.
The difference in the means is significant because a difference of 2.5 is very likely.
The difference in the means is not significant because a difference of 2.5 is very likely.
The difference in the means is significant because a difference of 2.5 is not very likely.
The difference in the means is not significant because a difference of 2.5 is not very likely.