# Quartiles, deciles and percentiles

Separator : space(s)
used with 'Custom percentile (N%)' option

This tools calculates quartiles, deciles and percentiles of a dataset.

Enter dataset numbers separated by a space.

## Percentiles and quartiles

Percentiles
In descriptive statistics, for a given dataset, the first percentile (or centile) corresponds to the value of the dataset such that 1% of the values in the series are less than that value.
We can generalize this way: the n-th percentile is the value of the series such that n% of the values in the series are less than this value.

Quartiles
The quartiles are a set of 3 values that divide the series into 4 parts :
- The first quartile (equal to the 25th percentile) is such that 25% of the values in the series are lower than it.
- The second quartile (equal to the 50th percentile) is such that 50% (or half) of the values in the series are less than it. This is simply the median.
- The third quartile (equal to the 75th percentile) is such that 75% of the values in the series are less than it.