Erica wants to know if warming up will help runners sprint faster. Twenty track and field athletes volunteered to participate in her study. She randomly assigns 10 athletes to warm-up for 10 minutes. All 20 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 11.9 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 Erica conclude from her study?

Question

anonymous · Answer

The difference in the means is not significant because a difference of 1 is very likely.

 The difference in the means is not significant because a difference of 1 is not very likely.

 The difference in the means is significant because a difference of 1 is very likely.

 The difference in the means is significant because a difference of 1 is not very likely

anonymous · Answer

there is a graph idk how to make it as a post

yanasidlinskiy · Answer

Upload it. Under the "type your reply" box, it has "Attach file".

anonymous · Answer

attachment

anonymous · Answer

@ganeshie8

anonymous · Answer

the thing i do not understand about this one is where am i finding "the Difference"?

anonymous · Answer

@radar is it possible that u might know the answer?

anonymous · Answer

@AnswerMyQuestions

anonymous · Answer

@Directrix

anonymous · Answer

@shrutipande9

anonymous · Answer

@AnswerMyQuestions i really need ur help plz

anonymous · Answer

I am not sure.

directrix · Answer

@kropot72

kropot72 · Answer

To find the average of the difference in the mean times of the re-randomized groups of 10, use the data in the dot plot to find the average difference by summing the data and dividing the sum by 54. This the sum of the negative difference is -48 and the sum of the positive differences is 14.8, giving a total of -33.2.
-33.2/54=-0.615 seconds.
This test of differences indicates that a difference of means of 1 second is not very likely, indicating that the last of the answer choices is correct.

anonymous · Answer

thank you soooo muchh!! @kropot72

kropot72 · Answer

You're welcome :)

anonymous · Answer

it was wrong

kropot72 · Answer

Sorry about that. I did not take my attempt far enough. The standard deviation of the data in the dot plot is 1.177. The z-score for a difference of 1 second is -0.33. Therefore the probability of a difference of 1 or more is 0.37. In this case the first of the answer choices is correct.