Correlation refers to the extent to which two variables are related across a group of participants. Consider scores on the College Entrance Examination Board’s Scholastic Aptitude Test (SAT) and first-year GPAs in college. Because the SAT is widely used as a predictor in college student selection, there should be a correlation between these scores and GPAs earned in college. Consider Example 1 below, in which SAT-V refers to the verbal portion of the SAT.1 Notice that there is one group of students, with two scores for each student. Is there a relationship between the two variables?