Answer:
Class A shows the most consistency in the number of hours slept per night because the standard deviation is the lowest.
Step-by-step explanation:
The standard deviation of a set measures how close the measures of this set are, that is, how consistent they are.
The lesser the standard deviation is, the higher the consistency is.
In this problem, we have that:
Class A has the lowest standard deviation.
So:
Class A shows the most consistency in the number of hours slept per night because the standard deviation is the lowest.