Question

Of 20 test scores, three are less than or equal to 87. What is the percentile rank ofa test score of 87?

Answer 1

We know that in a data set of 20 test scores, we have 3 that are less than or equal to 87.

A percentile rank describes the percentage of people in the comparison group who scored below a particular score.

In this case, a percentile rank of 87 correspond to:

$PR_{87}=\frac{20-3}{20}=\frac{17}{20}=0.85=85\%$

This means that the students that score 87 or more performed better than 85% of the other students as there are 17 out of 20 test scores that are under 87.

Answer: the percentile rank of a test score of 87 is 85%.