# Percentile

A percentile (or a centile) is a measure in statistics. It shows the value below which a given percentage of observations falls.

For example, the 20th percentile is the value (or score) below which 20% of the observations may be found. The 35th percentile is the value below which 35% of the data may be found. In general, the i-th percentile, written as ${\displaystyle P_{i}}$,[1] is the value below which i percents of data may be found.

In statistics, a large set of numerical data is sometimes divided into 100 groups, each with 1% of the data. The data are arranged in ascending order. Each of the 99 dividing points is called a percentile of the data set.

Some of the percentiles have special names. For example. the 25th, 50th and 75th percentiles are called the first, second and third quartile, respectively.[2] The 50th percentile is also called the median.

## References

1. "List of Probability and Statistics Symbols". Math Vault. 2020-04-26. Retrieved 2020-10-13.
2. "Percentiles". www.mathsisfun.com. Retrieved 2020-10-13.