# Quartiles

- Statistics which divide the observations in a numeric sample into 4 intervals, each containing 25% of the data. The lower, middle, and upper quartiles are computed by ordering the data from smallest to largest and then finding the values below which fall 25%, 50%, and 75% of the data.

- The middle quartile is usually called the median.

- Quartiles are special cases of percentiles. The lower quartile, median, and upper quartile are the same as the 25th, 50th, and 75th percentiles.

- Box and whisker plots provide a graphical summary of a data sample in terms of its quartiles.

**See also: **Box Plot, Inter-Quartile Range, Median, Quintile.

**Subjects: ** Statistics