You want to determine the relationship between caffeine intake and performance on a mid-quarter exam.As students sit down to take the exam,you ask them to write the number of cups of tea,soda,or coffee they ingested two hours prior to the exam.You also obtain their exam scores.You calculate the correlation coefficient between the two variables to be +0.82.What can you conclude?
A) The more caffeine students consumed,the better their scores.
B) 82 percent of the students consumed caffeine prior to the exam.
C) Drinking coffee caused better scores.
D) The more caffeine students consumed,the worse their scores.

Question

Quizplus · Accepted Answer

The positive correlation coefficient of +0.82 indicates a strong positive relationship between caffeine intake and exam scores. Therefore, we can conclude that the more caffeine students consumed, the better their scores. Option B is incorrect because the correlation coefficient does not tell us anything about the percentage of students who consumed caffeine. Option C is incorrect because we cannot establish causation based on correlation alone. Option D is incorrect because the correlation coefficient is positive, indicating that as caffeine intake increases, the exam scores also increase.

You Want to Determine the Relationship Between Caffeine Intake and Performance