Question

the table shows the test scores of students who studied for a test as a group (group a) and students who studied individually (group b).
student test scores (out of 100)

group a	84	80	77	96	92	88	88	84	92	100
group b	92	86	85	87	83	85	83	76	80	88

which would be the best measures of center and variation to use to compare the data?
the scores of group b are skewed right, so the mean and range are the best measures for comparison.
both distributions are nearly symmetric, so the mean and the standard deviation are the best measures for comparison.
both distributions are nearly symmetric, so the median and the interquartile range are the best measures for comparison.
the scores of both groups are skewed, so the median and standard deviation are the best measures for comparison.

Explanation:

Step1: Analyze data distribution

By looking at the data of Group A and Group B, we can see that the data points are evenly - spread around the middle values for both groups, indicating nearly symmetric distributions.

Step2: Recall measure - selection rules

For symmetric distributions, the mean is the best measure of center as it takes into account all data values, and the standard deviation is the best measure of variation as it measures the average distance of the data points from the mean.

Answer:

Both distributions are nearly symmetric, so the mean and the standard deviation are the best measures for comparison.