Answer:
The 12 children selected in Mrs. Smith's kindergarten class.
Step-by-step explanation:
In this case, the population studied are all children in Mrs Smith's kindergarten class, the sample chosen for the study are the 12 children selected in Mrs. Smith's kindergarten class, and the analyzed variable is the number of hours children sleep.
Therefore, since the question asks for the sample, the answer is The 12 children selected in Mrs. Smith's kindergarten class.