Final answer:
The difference in means between the first two groups would have to be greater than 8.4 in order to be considered significant.
None of the given options is correct
Step-by-step explanation:
In this experiment, the researcher performed 200 iterations where she combined the groups and selected two new groups each time. The researcher then calculated the difference in means for these new groups and plotted the distribution of these differences. From the provided chart, we can see that the normal distribution of the differences in means is given in percentages.
To determine the significance of the difference in means between the first two groups, we need to compare it to the distribution on the chart. The chart shows that 34% of the differences fall between 1.23 and 4.86, while 66% of the differences fall between 4.86 and 8.4.
Since the researcher wants to know how great the difference in means between the first two groups should be in order to be considered significant, we need to consider the distribution beyond the 66th percentile. This means that the difference in means should be greater than 8.4, as this is the upper limit of the distribution on the chart.
In conclusion, for the difference in means between the first two groups to be considered significant in this experiment, it would need to be greater than 8.4.
None of the given options is correct
Your question is incomplete, but most probably the full question was:
A researcher performed an experiment with two groups. She found the difference of the means for each group. Then she combined the groups, chose two new groups, and found the difference between the means of those new groups. She repeated this process 200 times. The normal distribution of the difference in the means she found is given below. How great would the difference in means between the first two groups have to be in order to considered significant?
on the chart:
34%
1.23 4.86.6 8.4