Final answer:
The sample in the study is a group of volunteers which included individuals with 8 hours of sleep, who were then compared to sleep-deprived individuals to determine the effect of sleep on math test performance.
Step-by-step explanation:
The sample used in the study mentioned is the group of volunteers who had 8 hours of sleep and their performance on a math test compared to the performance of sleep-deprived participants. Given the context of the study, it is likely that the sample consisted of individuals who were available and willing to participate in research comparing cognitive performance after varying amounts of sleep.
We can infer that the study's aim was to examine the relationship between sleep duration and cognitive function, particularly mathematical problem-solving ability. This research contributes to a broader understanding of the cognitive benefits associated with getting an optimal amount of sleep, which includes enhanced creative thinking, language learning, inferential judgments, and possibly the processing of emotional information.