Clearly there is overlap in the data: The maximum of the 6th-grade dataset is 60 while the minimum of the 7th-grade dataset is 54.
Since the two datasets have means 55 and 61 with their respective deviations 2.2 and 2.4, it is very likely that the Sonya will see two humps in the dot plot and hence will be able to deduce there are two separate datasets being plotted jointly (assuming normal distribution).
The dot plot can show which dataset has the most variability, however, in this case the standard deviations are comparable (2.2 and 2.4) and so, given the strong overlap and the small counts of the population, Sonya might not be able to discern this characteristic from the box plot
