Answer: Class 3
Step-by-step explanation:
Standard Deviation is a measure of dispersion which means that it measures how far apart the values in the dataset are from the mean.
If the values in the dataset are close together, the standard deviation will be smaller. The reverse is true.
The class with the widest range is there the class with the highest Standard Deviation.
With a SD of 7.8, Class 3 has the widest range of scores.