Julie has found that the number of hours she sleeps each night is related to the scores she receives on quizzes the next day. As her sleep approaches eight hours, her quiz scores improve; as her sleep drops to five hours, her quiz scores show a similar decline. Julie realizes that:
A) she should sleep about 10 hours a night to ensure 100% quiz grades.
B) there is a positive correlation between the number of hours she sleeps and her quiz grades.
C) her low quiz scores are caused by sleep deprivation the night before a quiz.
D) there is a negative correlation between the number of hours she sleeps and her quiz grades.

Question

Quizplus · Accepted Answer

The statement mentions that as the number of hours of sleep increases, quiz scores improve, and as the number of hours of sleep decreases, quiz scores decline. This indicates a positive correlation between the number of hours of sleep and quiz grades. Option A is incorrect and unrealistic, as 10 hours of sleep is generally not recommended for adults. Option C makes an assumption that there is always low quiz scores, which is not mentioned in the statement. Option D is incorrect as it suggests a negative correlation between the number of hours of sleep and quiz grades, which contradicts the statement's findings.

Julie Has Found That the Number of Hours She Sleeps