Question

pretend that you want to determine the relationship between caffeine intake and performance on a midterm 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?
d) students who drink caffeine are smarter than those who dont drink caffeine.
c) drinking coffee caused better scores.
a) the more caffeine students consumed, the better their scores.
b) 82 percent of the students consumed caffeine prior to the exam.

Explanation:

• Option D: Correlation doesn't imply intelligence differences, so this is wrong.
• Option C: Correlation (r = +0.82) shows association, not causation. So "caused" is incorrect.
• Option A: A positive correlation coefficient (+0.82) means as one variable (caffeine intake) increases, the other (exam scores) tends to increase. So this matches the correlation interpretation.
• Option B: Correlation coefficient doesn't represent the percentage of students who consumed caffeine. So this is wrong.

Answer:

A) The more caffeine students consumed, the better their scores.