Quantiles are values that divide a dataset into equal parts. For example, the median is a quantile that divides a dataset into two equal parts. Other common quantiles include the quartiles (which divide a dataset into four equal parts) and the deciles (which divide a dataset into ten equal parts).

Quantiles are often used in statistical analysis to describe the distribution of a dataset. They can be used to identify outliers, to compare datasets with different scales, and to calculate summary statistics such as the interquartile range.

There are different methods for calculating quantiles, including the interpolation method and the nearest-rank method. The choice of method can affect the values of the quantiles, particularly for small datasets or datasets with extreme values.