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? 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
A. The difference in the means is not significant because a difference of 1 is very likely.
B. The difference in the means is not significant because a difference of 1 is not very likely.
C. The difference in the means is significant because a difference of 1 is very likely.
D. The difference in the means is significant because a difference of 1 is not very likely.
A. The difference in the means is not significant because a difference of 1 is very likely.
B. The difference in the means is not significant because a difference of 1 is not very likely.
C. The difference in the means is significant because a difference of 1 is very likely.
D. The difference in the means is significant because a difference of 1 is not very likely.
2 answers:
Answer:
There are two groups, each consisting of 10 members. Group A which consist of 10 members, has warmed up for 10 minutes.
As warming up before running will make the runners to run for longer time and to run fast if they are running for shorter duration of time.
Now, Mean for each group was calculated.
Mean for the warm-up group =10.9 seconds
Mean for other group =11.9 seconds
Difference in mean of two group = 11.9-10.9=1
Now, Erica randomized the data 54 times, and the differences are plotted in the dot plot.
As, difference of mean=1, which occurs for maximum of 12 times.
As, difference in means is not too large.
So, option A : The difference in the means is not significant because a difference of 1 is very likely is true option describing this group of 20 who sprints in two different groups each having 10 member.
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