The dot plot shows the number of classes per semester that a group of boys and girls have chosen to take in their freshman year of college. Which statements correctly describe the two data sets?



The difference of the means is 1.5.
The difference of the means is 0.5.
The difference of the means is about one-third the mean absolute deviation of either data set.
The difference of the means is 1.
The difference of the means is about one-half the mean absolute deviation of either data set.