Angela took a general aptitude test and scored in the 89th percentile for aptitude in accounting. (a) what percentage of the scores were at or below her score?

If Angela scored in the 89th percentile for aptitude in accounting, it means that she scored higher than 89% of the people who took the test. Therefore, the percentage of scores that were at or below her score is 89%. The interpretation of a percentile rank is that it gives the relative standing of a score within a group. Thus, Angela is ahead of 89% of the test takers, and only 11% scored as high as or higher than she did.

Extra: Percentiles are used in statistics to give you a number that describes the value that a given percent of the values are lower than. When someone says that a score is at the 89th percentile, it's essentially a way to rank scores in a way that's independent of the actual scores themselves. It's about the position relative to others.

Understanding percentiles can be very useful in various aspects of life, such as in academic testing or understanding growth charts in medicine. When a child is at the 50th percentile for height, it means that they are taller than 50% of their peers. In tests like Angela's aptitude test, scoring in a higher percentile is often seen as desirable because it indicates a higher relative performance compared to other test takers. It's important for students to understand that percentile ranks are not the same as the percentage of questions they got right on a test. Percentile is about your position in a group, whereas percentage correct is about the fraction of questions answered correctly.