Professor Izadi is interested in the association between sleep and cognitive performance.He surveyed his students about the number of hours they slept the night before the exam and then correlated these scores with their test grades.He found a +.81 correlation between these two variables.What does this result mean?

Question

Quizplus · Accepted Answer

A correlation coefficient ranges from -1 to +1, with +1 indicating a perfect positive correlation and -1 indicating a perfect negative correlation. In this case, a correlation coefficient of +.81 indicates a strong positive correlation between sleeping the night before an exam and test grades. Thus, choice C is the correct answer.

Professor Izadi Is Interested in the Association Between Sleep and Cognitive