In descriptive statistics, a quartile is any of the three values which divide the sorted data set into four equal parts, so that each part represents 1/4th of the sample or population.
Thus:
- first quartile = lower quartile = cuts off lowest 25% of data = 25th percentile
- second quartile = median = cuts data set in half = 50th percentile
- third quartile = upper quartile = cuts off highest 25% of data, or lowest 75% = 75th percentile
The difference between the upper and lower quartiles is called the interquartile range.
Calculating quartiles
See Quantile for methods. The quartile is calculated as the 4-quantile.
See also
External links