Julie Finds That the Number of Hours She Sleeps Each

Multiple Choice

Julie finds 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 8 hours, her quiz scores improve; as her sleep drops to 5 hours, her quiz scores show a similar decline. Julie realizes that there is a _____ correlation between her hours of sleep and her grades.

A) negative
B) positive
C) neutral
D) causative