A value on a scale that indicates the percent of a distribution that is equal to it or below it.
A score belongs to the 78th percentile, for example, if it is greater than 78% of the scores but it is not greater than 79% of the scores.
This procedure divides the scores into 100 percentiles, numbered 0th through 99th.
A group of 10 consecutive percentiles is called a decile.
25 consecutive percentiles are called a quartile.
See also: Deciles.