A percentile is a statistic that gives the relative standing of a numerical data point when compared to all other data points in a distribution. In the example PM − 66, P.84 is called the percentile rank and the data point of 66 is called the percentile point. The .84 in the percentile rank of P.&j is a proportion that tells us the relative standing of the percentile point of 66 compared to all other data points in the distribution being examined. Reporting percentiles can be a useful way to present data in that it allows an audience to quickly determine the relative standing of a particular data point.

By itself, a raw score or data point says little about its relative position within a data ...