Question

1. a college statistics teacher gives a 20 - point test to ten students. the scores are below. find the percentile rank for a score of 15. 18, 15, 12, 6, 8, 2, 3, 5, 20, 10

Explanation:

Step1: Arrange scores in ascending order

0, 2, 3, 5, 6, 10, 12, 15, 18, 20

Step2: Use percentile - rank formula

The formula for percentile - rank is $PR=\frac{c}{n}\times100\%$, where $c$ is the number of scores less than or equal to the score of interest and $n$ is the total number of scores. Here, $n = 10$, and the number of scores less than or equal to 15 is $c = 7$.

Step3: Calculate the percentile - rank

$PR=\frac{7}{10}\times100\% = 70\%$

Answer:

70%