Editing Percentile (section)

===The nearest-rank method===
[[File:Percentile.png|thumb|450px|The percentile values for the ordered list {15, 20, 35, 40, 50}]]
One definition of percentile, often given in texts, is that the ''P''-th percentile <math>(0 < P \le 100)</math> of a list of ''N'' ordered values (sorted from least to greatest) is the smallest value in the list such that no more than ''P'' percent of the data is strictly less than the value and at least ''P'' percent of the data is less than or equal to that value. This is obtained by first calculating the ordinal rank and then taking the value from the ordered list that corresponds to that rank. The [[Ordinal scale|ordinal]] [[Ranking|rank]] ''n'' is calculated using this formula
: <math> n =  \left \lceil \frac{P}{100} \times N  \right \rceil. </math>
* Using the nearest-rank method on lists with fewer than 100 distinct values can result in the same value being used for more than one percentile.
* A percentile calculated using the nearest-rank method will always be a member of the original ordered list.
* The 100th percentile is defined to be the largest value in the ordered list.