Looking for a relationship (correlation) between the ranking of students in their high school class (who had the highest GPA, the second highest, third highest, etc.) and the ranking they receive on a college entrance exam (who had the highest score, the second highest score, the third highest, etc.).
On the other hand, if you wanted to look at the relationship between actual GPA's and actual scores on the exam (instead of rankings) then you would use a parametric test.
On the other hand, if you wanted to look at the relationship between actual GPA's and actual scores on the exam (instead of rankings) then you would use a parametric test.